Previously known as Fennec, Firefox 4 beta is now available on Mozilla's website. Don't go look for it on Market, you won't find it and you'll get a "Fake Mozilla Firefox" in the results.
This release delivers a rich set of features, including pinch-to-zoom, which is now supported on multitouch-capable devices, and the Awesome Screen, which instantly gives you access to your recent history, bookmarks and tabs just by tapping in the Awesome Bar. See the release notes for a full list of features included in this release.
Download your free copy here.
Watch the demo.