Video/audio from PC to PC: Broadcasting PC gameplay to Justin.TV using another PC

[gman]

Hi, i was wondering if its possible to send video/audio from one computer to the other, i have no idea how to achieve this.

What i want to do is for pc2 to recieve video/audio from pc1 so i can use pc2 to stream everything that happens on pc1.
For example as if you connect your console to your pc to record/stream it but with 2 pc's instead, not that i have any experience of this either.

Why do i want to do this you ask? well i want to lighten the load on pc1 by making pc2 have flash media encoder to encode and stream its desktop.

Do i need a capture card on pc2 thats connected to pc1's video out? and if yes, is there any guide or something similar?
Thanks.