Broadcast-live-video-from-desktop business is getting crowded. 

Ustream is the last company launching a new desktop client. It is called Ustream Producer, and it includes high-video quality and editing tools to for live streams. 

We are not talking about broadcasting via your web browser, using Flash to access your PC's webcam. We are talking about more complex broadcasts than a single stream. You can have simultaneously two streams or more.

With a desktop client like Ustream Producer (see picture below) you can stream in HD and H.264. 

The premium version ($199) lets you use multiple cameras and graphic overlays from the same setup, while the free version lets you include additional streams that are being broadcast from other computers. You can also integrate previously recorded video, and share your desktop screen.

Competitor LiveStream offers a similar production tool called Procaster. 

Third party applications like Wirecast allows you to stream to multiple livestreaming services, like Justin.tv, Livestream.com, and Ustream.