Tweak Windows Here's a couple of sites to help you get the crap out of Windows so your system can perform better.

Annoyances.org - this based on books of the same name. You won't find all the books contents here, but a lot of tips, articles, etc., to help out anyway.

XP Tune Up - this site is pretty much for XP Pro, though most of the tips will work with XP Home as well.

Windows Support Center - this isn't an MS site, but it's staffed by Windows Pros.