Just in case anyone wants a copy of sp1 to install (legally or not) without going through microsoft, you can download a full copy of the installer in Kazaa. The copy I found was called "Windows XP Service Pack 1" and was around 130 MB. It includes the upgrade for both home and pro editons. It does require a valid cd-key to use, though. If you turn off auto-update, you can install the patch without ever contacting MS. I even installed it with my internet connection unplugged, and my firewall software never gave any indication of it trying to register, either during or after the update.