Kit is: Modest PC Running XP, hard wired to the router, and wireless to a laptop with the same OS. SBC ? router (Tiscali deal BB and phone. Bad news that!!!

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I managed to set up my friends system so that he could print from his laptop via the office computer upstairs, but had to stop there because of time constraints.
Right now he's carrying data with a USB 'Stick'
He doesn't want to e-mail himself, but would like to copy pictures and letters from one computer to the other. What is the best way to do this?