Anyone following the Firefox 3 Alpha will be happy to know that alpha release 5 is now available. “Gran Paradiso” now enters into revision 1.9, bringing with it a horde of bugfixes and improvements. They've introduced a new password manager, a better crash reporting system, native controls for OS X and a slew of bug fixes.
If you're wanting to be a part of the alpha, they make binaries and source available as usual for download. Keep in mind, however, it is alpha software intended for development and as such has no support and could very well break all over the place. But that's half the fun, right? The Windows binary weighs in at about 6.2MB.