Recently, I wrote “How To: Convert Videos for the iPhone (or any mobile device)” on Mashable.com. I covered some of the best ways to convert videos and copy them to your iPhone for free. Well, the beauty of blogging is that no matter how thorough you are when it comes to research there are always resources out there that you miss for whatever reason. Thankfully, however, readers are more than happy to share your omissions in the comments section (sometimes they do it politely, sometimes not so nicely). In any event, it’s wonderful to learn about new links and software that only adds value to your post thanks to the comments.
Well, unfortunately, it’s considered taboo to edit any post that’s gone to press on a big time blog such as Mashable so all of the golden nuggets must remain buried in the comments. So I’ve decided to take all of my links and resources and combine them with the valuable suggestions that readers have made in the comments and developed this list which I will continue to update whenever I find new resources, which I have since we published that piece only days ago.
So, save this bookmark if you want to track the best ways to convert videos to your iPhone or mobile device and check it every once in a while.
Online Converters
ConvertTube is a free service that converts online videos to several formats including the MP4 format that you need for Apple devices. Simply paste the video URL from sites like YouTube, Google video, MetaCafe, etc. and select the desired output format.
While the service is extremely simple to use, it must be mentioned that it can take an eternity sometimes for this service to convert even the smallest video. Sometimes it just times out or fails without any explanations. Still, most of the time it will do the trick if you want to do a quick conversion or two. For more than a handful, you’ll be better off with another solution that handles batch processing.
VideoDownloader is similar to ConvertTube except it doesn’t provide you with any output options. What you see is what you get when you download the video from the services they support: YouTube, Google, BlipTV, DailyMotion and a few others. So, if you can’t download the video .mp4 format, you’ll have to convert it with another separate utility which isn’t a big deal or expense.
Movavi Online Convert is another online video converter that provides the unique ability to download and convert up to five different online videos as one video. You can add all of the URLs and the service will send you an email with a link to download when it’s done. It could take a long time, so it’s not good if you’re in a hurry.
Zamar converts online like the others and also converts other forms of media such as photos.
YouTube now allows you to download many of their videos in MP4 format which means you don’t even have to convert the the video! You simply download and copy it to your iTunes which will sync it on your iPhone! Look for the download MP4 link beneath the embed code. 
Free Software Converters
Videora offers an impressive suite of tools for converting and editing videos for free. The video files can be avi, divx, xvid, flv, x264, vob, mpeg, DVDs, YouTube, etc. Any of these videos can be converted into the proper video formats (MPEG-4, H.264) that play on the iPhone 3G. Here’s Videora’s Video Converter for the 3G iPhone, which does an excellent job changing existing formats of videos you own into the MPEG-4 H.264 format. Their other converters will do the same trick for other devices such as the iPod, nano, Tivo, Sony Playstation Portable (PSP), Xbox360 and more.
There are many options when you’re converting your videos for your iPhone. Obviously, the better the quality, the larger the file size. Ultimately it’s a personal decision everyone has to make on what’s more important: space on your iPhone or audio/video quality. Personally, I prefer to stick with the highest quality video and audio because the experience is so worth it. You just have to pick and choose which videos you want to keep on your iPhone. If you have the 8 GB then perhaps you should compromise a little and choose medium or high levels of quality for video and audio. Play around and see which results you like best.
Note: All of the converters are free and appear to be spyware free without any problems. They do offer a Videora 2.0 software and service package for a fee but that isn’t required for any of these converters.
Free Studio Manager offers a staggering 20 free audio/video tools. You can choose to download all 20 utilities as one package or pick and choose those you need.
There are a few that focus on converting videos for the iPhone. For example, there’s the YouTube to iPhone converter that downloads YouTube videos and automatically converts them to the appropriate iPhone MPeg-4 H.264 format for you. Keep in mind that many of the videos on YouTube are now in the .MP4 format, so the conversion process will skip that part once it’s downloaded and determines what format the video is in. There’s a handy batch mode feature which allows you to download several YouTube videos at one time, making this process more efficient.
Here’s the Video to iPhone Converter which lets you convert any video file that you already possess without needing to download any videos from YouTube or elsewhere. The important thing to point out about this utility is that it provides the highest quality video output in this roundup, whereas Videora can generate a standard quality MPEG-4 H.264 file (24 fps, 480×320 ACC 128Kbits). Free Studio’s converter can generate a High Quality MPEG-4 H/264 file at 30 fps, 480×320 ACC 192Kbits. It might not be that big a deal to most people, but it will make a huge difference to many
of you.
Any Video Converter is another free converter for windows that will convert a boatload of formats to iPhone friendly format: DivX, XviD, MOV, rm, rmvb, MPEG, VOB, DVD, WMV, AVI, etc.
xviD4PSP is an excellent package for Windows 
Sucubus has a free windows tool for searching and downloading/converting videos
HandBrake is an excellent package for the Mac OS and now Windows too!
Squared5 offers a free converter for Mac OS and Windows
iSquint is no longer updating its converter for Mac users but you can still use the last version they released.
BetterYouTube is a free Firefox add-on that lets you download YouTube videos as mp4 format
MediaCoder is a free download for Mac
Gom is free for windows
Commercial Video Converters (NOT Free)
***Pai’s Favorite!***
Replay Converter is a media converter from Applian Technologies which is well-known for its Replay Capture Suite that includes the converter and several other products. Their most popular product is the Replay Capture tool that allows you to record any streaming audio or video much like a Tivo for the Internet.
Mac YouTube Converter works for the Mac and costs about $30
MelodyCan converts for a price
AimerSoft for the Mac $35
Video for Other Platforms
Okay, okay, we won’t ignore you CrackBerry heads. Here’s AVS Video for Blackberry that’ll help you convert videos for Blackberry devices.
All of the software packages referenced above were for the Windows OS, so MAC OS users won’t be able to use them. There was a free video conversion tool for the Mac OS from iSquint.org, but they’ve stopped supporting their product. However, it’s become open source on SourceForge, so others might continue the development for this tool for the Mac OS.
How to Copy Videos to Your iTunes and iPhone
After converting all your videos to the appropriate video format for your iPhone, you’ll need to store them on your computer in the right place so that iTunes can do its job and copy the videos to your device. The best thing to do is create a new folder on your system called, for example, iPhone Videos, and copy the newly converted videos to that folder. You can also get into the habit of converting new videos straight to that folder to save steps and time later on.
Once you have your videos in one place, simply launch iTunes, click on the Movies icon and click the File menu. Select Add Folder to Library, then select the new iPhone Videos folder that you created. iTunes will then suck in all of the videos that it finds in that folder.
Click on your iPhone under DEVICES and select the Video Tab. Then Enable the Sync Movies option, and select all of the videos that you want to copy to your iPhone. You can pick and choose which ones you want at any time.
The next time you sync, all of the videos you selected will be copied to your iPhone. You can view them by launching the iPod app on your iPhone and selecting the video option.
Must-Have Video Players & Utilities
Every system comes with a video player but these standard players don’t support that many formats. For example, Microsoft’s Windows Media Player does not support the Flash (.FLV) video format, which means you can’t download and play most of the videos you find online these days.
VLC Media Player is an open source media player that supports a plethora of video and audio formats. It loads quicker than most of the bloated media players and can handle most of the formats you’ll ever run into. Here’s a feature list.
Conclusion
This was just a sampling of the many cool tools out there that can help you download and convert videos into a format that you can use on your iPhone or any other device. In most cases, you can do so for free. However, some of the premium packages and services appear to be well worth their nominal fees when you consider everything they provide. In any case, you can now enjoy any of your favorite videos on your iPhone or other mobile device.