Mozilla has finally released the first Firefox 4 beta, and you can download it now. Firefox 4 is a major step up from the previous version, with a redesign of the user interface, greatly improved HTML5 support, hardware-accelerated HD video playback, better add-on support, and a bunch of other new features. Luckily, the Mozilla team has pulled everything together in a blog post to fill you in on all the fun. With Google Chrome gaining on Firefox marketshare, you can bet Mozilla is gonna be pushing the new hotness found in 4.0 hard. You can download Firefox 4 beta 1 now.