I've been experimenting with this for Fireside Chat, as well as a few of my other projects. Like anything, there are a few different ways you can go.
The Easy Way
If you can get one laptop and a few different webcams, you can put each camera on a tripod, and use a virtual switcher like ManyCam to switch from camera to camera. You can save this video, or stream directly to Facebook or YouTube.
For audio, I'd get an mixing board like
this one which lets you have up to 4 XLR mics plugged in, and then plug that into your CPU via USB.
If you want to throw around some other ideas, PM me. I have a few more ways too.