On: AIM AV

This is presumably using Adobe's new RTMFP[1] which means it's all P2P. Same way Chat Roulette works.

It's extremely easy to create this kind of thing now (as in hours of work for a simple version).

http://en.wikipedia.org/wiki/Real_Time_Media_Flow_Protocol

Are there any good open-source implementations?

assuming you mean RTMFP: https://github.com/OpenRTMFP/Cumulus

Last time I checked, red5 was trying to reverse engineer the protocol. Not sure how far they are.

Of what? Flash? RTMP? 4-way video chat?

If you want all that in a single package, no.

What if I want to record. Help please?