Hello and Welcome to the Forum.
Please note that iCloud (Internet backup and sync) requires Windows Vista or Windows 7.
However, a local Sync is compatible with Windows XP (although I believe SP3 is required).
Did you enable the device settings in iTunes (on XP) while your iPad is connected via USB?
This setting can be found below the Options heading on the "Summary" tab of the device settings (you might need to scroll down to see it). This will permit a WiFi sync to take place automatically each time your iPad is locked and plugged into a power source. You can also manually initiate the WiFi Sync using the Sync button in iTunes, or on the device from .
Also ensure you've selected bookmarks to sync iniTunes.