The new Firefox Beta from Mozilla can be downloaded from Softpedia
Mozilla has officially announced that the sixth Beta release in the Firefox 22.x branch is now available for download on the Linux platform.The Linux binaries for Mozilla Firefox 22.0 Beta 6 have been made available and you can download it now, without having to install anything.
There aren't too many details about the changes and improvement in this latest version of Firefox, but Mozilla is getting closer to a stable release.
A detailed list of upcoming features can be found on the official website.
Download Mozilla Firefox 22 Beta 6 for Windows
Download Mozilla Firefox 22 Beta 6 for Linux
Download Mozilla Firefox 22 Beta 6 for Mac OS X
Remember that this is a development version and it should NOT be installed on production machines. It is intended for testing purposes only.