It's currently codenamed Fennec.

This is an early developer release of the mobile version of Firefox, for testing purposes only, intended to:

  • get wider community feedback on our approach to the user experience
  • engage Mozilla community teams, including localizers, add-on developers, and testers
  • get feedback from Web developers

The focus of development so far has been on building a new user interface that reflects Firefox's design principles, and adds touch screen support and other features that are appropriate for mobile phones and other handheld devices. We plan to do further alpha releases which focus on performance, including projects like TraceMonkey, speculative parsing, and many Fennec and Gecko optimizations. But in the meantime, we feel it is important to make this early release available to continue to grow the community and gather feedback as early as possible in the development process.

Of particular note: You can install a version for Windows to see how its coming along.

Looking good, though I'd argue that the address bar area is way too big right now. I assume that will auto-hide.

Thanks to Sebastian V. for the tip.