Noticed I hadn't posted this here before, so here goes:
As you'll read on the site itself, in response to some sites beginning to charge subscriptions for their tweak tips, also as an update and collation of my XP optimization guide and other computer-related guides, I launched my free tweak-site XPfree.org earlier this year-
it's free advice for XP/2k systems (and some other operating systems).
The XP advice applies equally well to Vista in some scenarios, and there's other info on the site which may be of use to some others-
Just updated it today, varying minor changes, added networking optimisation tips, as well as instructions on how to enable UDMA66 for IDE drives in XP/2k - strangely not enabled by default.