As I'm sure you know by now, we've updated the XPSP2 page in the Security Developer Center with links to the downloads available. In addition, a number of other pages have been updated on Microsoft.com. Here's a short list of the articles and pages that I'm reading through today:
List of fixes included in Windows XP Service Pack 2
Release notes for Windows XP Service Pack 2
Windows XP Service Pack 2 (SP2) for Developers - Lots of good info here.
Changes to Functionality in Microsoft Windows XP Service Pack 2
And just a quick note about the checked build we're linking to from our XPSP2 page. This is a great build to install on a test machine that you want to run a debugger against, but it will probably mess up your workstation if you install it on a machine you're trying to work on. If you're looking for the build to run locally, use the release build.