Mozilla has just released Firefox 16. Firefox 16 features VoiceOver option if you are using OSX among many additional stability tools to enhance the user experience. If you are a developer you will be happy to see all the additional developer tools that comes with Firefox 16.
Here is what’s new:

Firefox on Mac OS X now has preliminary VoiceOver support turned on by default.
Initial web app support (Windows/Mac/Linux).
Acholi and Kazakh localizations added.
Improvements around JavaScript responsiveness through incremental garbage collection.
New Developer Toolbar with buttons for quick access to tools, error count for the Web Console, and a new command line for quick keyboard access.
CSS3 Animations, Transitions, Transforms and Gradients unprefixed in Firefox 16.
Recently opened files list in Scratchpad implemented.
Debugger breakpoints do not catch on page reload.
No longer supporting MD5 as a hash algorithm in digital signatures.
Opus support by default.
Reverse animation direction has been implemented.
Per tab reporting in about:memory.
User Agent strings for pre-release Firefox versions now show only major version.

You can download firefox 16 here: