Hi,
The easiest way would probably be to start your Mac in Target Disk Mode. What this basically does is it allows your broken Mac to function as a hard drive for the other Mac, through a Firewire cable. Connect the two Macs, start the "good" one, and then hold down the 'T' key while the "bad" one is starting. You should then see its hard drive appear on the first Mac.
Network booting is kind of complex to setup, you'll need a special server. I've never done it before, but if you're really interested in doing it, there's lots of information on the web regarding this.
John A
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