Microsoft have released a new build of Windows XP SP2 to official beta testers this evening. Although it was announced that the next build would be RTM it seems Microsoft want to gain some last minute feedback before the RTM in August. This build is interim between RC2 and RTM and will not be made available to public preview.
Microsoft previously denied our reports of a possible new build as "untrue and inaccurate", doh ;)
We"re also able to confirm you can install this build onto any SP2 from 2138 to 2162.