The first beta of the upcoming new version of Firefox, 3.6, is now available for download.
This release is aimed only for the adventurous types, as it's not really a complete beta; technically, it's the test build of the first 3.6 beta version. In other words, if you decide to upgrade, expect bugs.
As far as new features go, you can expect better JavaScript performance, new version of the rendering engine (Gecko 1.9.2), and the uber-neat tab previews. As far as rotation-related functions, we don't have a laptop equipped with an accelerometer, but if you do, we'd like to hear your opinion in the comments!