Thanks to Bink for the tip! It seems Windows Service Pack 2 has been made avaliable on Windows Update V5, for anyone using XP SP1. Windows Update V5 & Service Pack 2 are the next major upgrades to Windows XP. The final of XP SP2 is still a little while away. 2138 (xpsp.040522-1636) is a little old compaired to the latest internal versions, build 2142 was compiled on Friday 28th May.
Download: Windows XP Service Pack 2 Build 2138 - 270mb (thanks tra)
View: Screenshot @ Bink.nu