Chi può provi! Da qui il download (aggiornato Beta 3)

Android
o Improved support for Android keyboards, both hardware and on-screen
o New Android-style menus
o Fixed a bug in opening links from other apps
o Support for uploading files
o "Save as PDF" command in the site menu
o Fixed rendering of Arabic and Farsi text (on devices with Arabic/Farsi fonts installed)
Firefox Sync
o New UI for simpler setup
o Support for custom Firefox Sync servers
Video
o Full-screen open video
o Improved audio performance
User interface
o Copy/paste in URL bar
o Search engines appear in the awesomescreen as you type
o Browse recommended add-ons through the add-on manager
For developers
o localStorage API
o orientation events (new on Android)
Support
o Crash reporting for crashes in web content

As well as these features from the previous Firefox 4 Betas:
o Sync - Shipping with the Firefox Sync feature built-in, Firefox 4 Beta synchronizes your Firefox history, bookmarks, open tabs, passwords and form data between your desktop and mobile.
o Add-ons - Firefox 4 Beta offers add-ons; small pieces of software that let you change the look and feel of your Firefox to fit your browsing lifestyle.
o Pinch-to-zoom (Android), double-tap, or use the volume rocker (Nokia N900) to zoom in and out
o Open tabs as thumbnails let you easily see and open the site you want
o Location-Aware Browsing gives you content and info relevant to your location
o Save to PDF in the Site Menu lets you archive important docs like tickets and directions to view offline
o Find in Page in the Site Menu lets you quickly find text on the webpage
o Share Page in the Site Menu lets you send content to email, Facebook, Twitter and Google Reader
o Forget Password in the Site Menu tells a website you no longer trust to forget your private data
o Add Search Engine in the Site Menu lets you quickly add a new search engine to your Awesome Screen
o Context Menu lets you Open in New Tab and Share by long tapping and holding a link
o Smart Tapping lets you tap on links, widgets and other Web content with accuracy
o Password Manager lets you choose to remember site password to avoid typing