Hi i have set up Videoconferencing for my company ,very cheaply and successfully.The refresh rates and imag quality are Real time ,more than 30 frames per second.
I have used a USB based WEB cam (DU-C300/560) and Microsoft netmeeting software does the rest for Poit to point.Thouh i should tell you that we have a 100Mbps LAN which is a big factor in speed.Also for multi party V.C., i have used teh free ware Cu.SEEme V1.0(all others are shareware) and a reflector available free from the web.and it works.