I tried "Ustream" yesterday and ran into an audio problem. The video streamed but there was no audio. I google searched to find a solution to the problem and then began to search for other streaming sites and found "Justin.tv" and then "Livestream." Justin.tv was not what I needed for my school site because you could not embed the code (or at least I could not find the place to embed after google searching for that answer) and I wanted something more mainstream. Fortunately, I found "Livestream" which is very similar to "UStream", except the audio works! It is pretty user friendly, was easy to create a channel and super easy finding the code to embed into my blog. If someone asked me which streaming site to use, I would recommend Livestream.
So what did I learn?
A. The audio does not work in Ustream for some odd reason.
B. You can always use google search to find answers however when you can't find an answer, find another tool that does work!! (there are so many out there!)