Check out Marratech Free

It allows you to set up a small server that will allow you to conference voice and video with up to 5 people for free. Very easy to set up and use.

Biggest draw back is that you cannot secure your conference room with a password so if the room is open anyone can join. Other than that it works pretty well with decent video and audio quality over the Internet.
http://www.marratech.com/free/