The first thing I'd try to do is to connect from your Mac to your PC simply by making sure you're in the Finder (click on the desktop anywhere, and it should now say "Finder" in the menu bar upper left), then connecting to your PC by typing ⌘K (or, in the menu bar, Go->"Connect to Server..."). If your PC is there, you should be able to connect to it, then just drag files across once the drive mounts.
Probably not the right way to do this, but works for me....
I'm a new Pbook owner, and I just connect the two laptops with an ethernet cable (directly, bypassing the router).
Find the IP address associated with your ethernet (click the apple in the far-upper-left corner of your screen-->"About This Mac"-->"More Info..."-->Click on the "Network" tab and find the address next to Ethernet).
On your windows laptop, just go into Windows Explorer and type in "//192.168.0.1", using your Ibook's IP address behind the double back-slash.
It may take a moment, but your windows laptop should connect/find the Ibook, then ask you for your Ibook's username/password. Then you should be set to go. Hopes this helps.