http://www.networkworld.com/news/2012/031212-firefox-11-slips-onto-stage-257192.html
The final release version of Firefox 11 isn't scheduled to make its official debut until Tuesday, but--as so often happens--it's shown up early.
Though some download links published in early reports appear to have been since taken down, there are still some third-party sites where a stable Firefox 11 can apparently be found, including Download Crew and Major Geeks.
At least one report suggests that one more update is still on the way before the browser's official release by Mozilla, however, so if you do check out an early version, you'd be wise to refresh it in a day or two.