is it possible to stream an AVI ("any" video) file just like a stream of a
webcam? My camera ist dead and I'll participate on a vide chat. I need
to send a video file just like a real webcam-captured image.

Thank you in advance,

I might be able to get you started:

Have a look at VLC Media Player (Freeware)
"VLC media player which can be used as a server and as a client to stream and receive network streams. VLC is able to stream all that it can read."

http://www.videolan.org/