Plain Old Telephoneline Based Video-conference systems
Via TV
Pros:
Uses regular phone lines which are cheap and commonly available
Moving color image
Relatively cheap price (8x8 ViaTV).

Cons:
Compatibility: you need one on each end of the line.
Slowish frame rate

Mitsubishi Lumaphone
Pros:
Ease of use. Familiar technology: your basic telephone
Regular phone lines
Portability
Sends still black and white image

Cons:
Need one on each end of the line
Not available anymore... If you have one, give us a call! :)