how to do Audio/Vedio streaming between web cams and back end servers?

[lichtj]

I want to implement an internet chat application, I mean, I want a front end, which connects a web cam (mic and speaker). So, I can send videos and audios to a back end server (do flash streaming? but I am not sure what good product out there I can use), and also send both A/V to another computer on the internet. In other words, need a front end that sends local a/v from webcam (&mic) to backend and receives remote a/v from backend to webcam (and speaker) + backend streaming server.

Any suggestions of techniques to be used? What back end flash streaming server should I sue? How to acquire A/V from web cam (& mic) and how to send A/V to web cam (&speaker) to play?

Thanks a lot!