While Microsoft is quick to downplay XP when comparing it to Vista, the legacy OS continues to shackle the hearts (and systems) of many. Fortunately, Microsoft just opened up their XP service pack 3 release candidate for general download -- that means you. SP3 RC was previously only available by invitation. Now get going, you'll need time to download all 336MBs of the last major update to the six-year old OS.
P.S. This is a "release candidate." The final SP3 release isn't expected until the first half of 2008.