Microsoft has just released an update to address the VML (VGX) issue

The update can currently be found on Microsoft Update and is titled
Security Update for Windows XP (KB925486)
http://www.microsoft.com/technet/security/Bulletin/MS06-055.mspx


It is recommended that the patch be applied immediately (after testing) unless a suitable mitigation strategy is in place.

Update: Also, note that if you applied the ACL mitigation (removing Everyone Read access from the DLL), you will need to undo that before this update will apply successfully. 

Thanks to everyone that submitted analysis, news, samples, malicious website reports, etc

More info:
http://isc.sans.org/diary.php?storyid=1727
http://blogs.technet.com/msrc/archive/2006/09/26/459194.aspx