We have been looking for a cost effective solution for Distance Learning equipment in our district. @jdbells60 recommended XMeeting. I downloaded the Open Source software and after about five minutes on the phone with our network engineer setting it up on our gateway we called a cart on the network and it worked like a charm. The video quality was good, but not as crisp or clear as a unit, but I was connected via wireless.
The coolest feature of XMeeting is that it can format the video screen at an angle, so it give it the feel that you are talking face to face instead of picture in picture.
If there is a school out there that does not have the money to buy a unit or would like to experiment I would highly recommend XMeeting for the Mac.