AT&T hasn't released an update yet, that is for WWE (European) versions. There are some serial numbers over at XDA that you can use.
This ROM is VERY fast compared to stock and even compared to all the other custom ROMs that were out there.
You could flash this. NATF v4.3 is also based on this build.
Check out this thread:
http://forum.xda-developers.com/showthread.php?t=483325