If you were hoping to get your hands on Firefox 3.6 before the end of the year, you're out of luck. CNET did some digging and discovered that release dates for both Firefox 3.6 and 4.0 have been pushed farther into the future.
Originally, Firefox 3.6 (which is bringing some cool personalization and customization features via new Personas functionality) was slated for an end-of-2009 release, while 4.0 was supposed to be delivered sometime in 2010. But according to Mozilla Wiki, Firefox 3.6 is now coming in the first quarter of 2010, while Firefox 4.0 is coming in late 2010 or even the beginning of 2011.