I read you installed winXP but you didn't reveal if you used the drivers Apple supplied.
I have a mac which I partitioned using bootcamp into 3 partitions. One for the mac osX, one for unix and one for windows. I put mac osX on first and joined to the wireless network setup in my house, no problem. I then installed winXP on the other partition but cannot get any internet. There is no wireless network icon coming up on the lower bar, as it should. And in the hardware list there are a lot of yellow exclamation marks for ethernet etc.