Who can offer some advice for setting up some video conferencing?

If you are going to tackle this, I am afraid I have to give some details about the challenge we are facing.

We are setting up a small conference room with a computer dedicated to drive some video and conferencing equipment. We have everything in place and running at 100% with the exception of the actual video conferencing camera. We thought just a decent web-cam would work but the problem we are having is the computer and all of its associated connections are in the corner of this room and the web cams in the local store all seem to be USB based. When we attempt to run the USB cable of any appreciable length to get the camera where it would need to be it doesn't work. (About 30' from the computer). We ahve even tried powered USB hubs and active extension cables, no luck. So we are really starting to think that a USB camera is not the best option.

So now that you understand the challenge, what CAN we use as a camera that would be recognized as a "web cam" so programs like Skype would see the video signal and allow us to do video chats? Would a standard video camera work? How about a security camera? The only problem is most of these are going to give us RCA jacks, BNC connections, or S-Video. If we bought a card for the computer that would accept Coax or RCA video in, would Skype even accept that as an acceptable "web-cam" option?

So if you have had some experience with this sort of thing and would like to make some recommendations... we are all ears!