Justin Kan and his team at Justin.tv just started a mobile live video webcasting about a month ago. I kind of understand the general concept of how the technology works. I can guess that they might use the following: head-camera, video transmitter that connects to the camera, cellular card that connects to the video transmitter, celluar card that attaches to the video receiver, video receiver that attaches to the webserver, video viewing software, video recording software, a wireless phone plan, and some programming codes for the website. But as to exactly how it works and what devices and software that they actually used, I am not too clear. Does anyone with a technical background know how it is put together? Please provide answer step-by-step with details.

I can’t vouch for it’s accuracy, but i’ll give you a general idea.
http://en.wikipedia.org/wiki/Justin.tv