Streaming Live Video Over the net

Something like this?

 

i setup two studios to do what you want. we had 4 video cameras on motorized mounts and 2 video other video feeds from a workstation and overhead projector. All the video feeds were piped in a box which you could select a feed. the video and audio where sent to a control room then the video was broadcast over a T1. OK, the video over T1 would be like you broadcasting via the cable channel. However, the important thing is the setup because you can split off the out going video and audio into a server for steaming over the internet. This is for ANALOG and I just noticed that you have a digital signal. oops. My bad, then you just a firewire cable, and firewire selector box.

This will anser a lot your question.
http://www.apple.com/quicktime/products/broadcaster/faq.html#2

You will however need a dedicated server for hosting the streams though, which will probably mean it will be a PC. Check this page with Mac and PC solution for streaming video.

http://etvcookbook.org/pc_dinners/streaming.html