file sharing with Wrt54G

I recently got a WRT54g to work with my Presario 2100z with the integrated
HP 54g adapter, and all is well wirelessly.
The range is quite good and surfing the net without wires is pretty cool. I
cannot however set up file sharing between the wireless laptop and my
desktop without screwing up the existing wireless connection to the net.
Ideally I would like to be able to back up my laptop drive to the desktop
periodically without having to connect the laptop to the router with cable.
I've used the network wizard twice and both times it fouled the previous
wireless connection. The desktop is running win2K pro Sp4 and the laptop is
winXP sp1. If anyone has any resources they could direct me to or any
advice I would be most appreciative.


Sandy