Utterz is referred to as the audio Twitter but now there is a Video Twitter launching called seesmic.
www.seesmic.com  (in private beta for now).

***Update***
 I just learned about Hictu which was labelled as the video twitter long before Seesmic!
Check this out, they even provide audio tweets so they’re like an audio & video twitter.
Too bad their look is so 1990′s.