Jakub Jelinek of Red Hat announced the release this morning of GCC 4.6.3. Over GCC 4.6.2 there's over 70 bug-fixes and other work. However, all of the exciting work meanwhile is going into what will become GCC 4.7.
GCC 4.7 will offer some performance improvements, new CPU support, language enhancements, mature Intel Sandy/Ivy Bridge support, and initial Intel Haswell support. GCC 4.7 should be officially released in March or April.
The release announcement for GCC 4.6.3 can be found on the GCC mailing list.