Here's an update to yesterday's post, it looks like Microsoft jumped the gun a little on SP3 for Windows XP.

Wired.com is reporting that the update encountered some issues with Microsoft's Dynamic Retail Application System and had to be pulled off the website. The report also states

The third service pack update for Windows XP has arrived today and is available for download on Microsoft's website. Many corporations are still very much behind Windows XP as Vista has proven to be a big disappointment for the business user. This newest service pack provides those users (and admins) with performance updates, security updates and hotfixes that have been released since the Service Pack 2 in August 2004.