Firefox on Android is imminent. Mozilla Fennec Pre-Alpha for Android has been released and is available for download but has been only tested on Motorola Droid and the Nexus One.
Being in pre-alpha, bugs might freeze your android phone. Just reboot it to get rid out of it. According to the developer Vladimir Mozilla Fennec Pre-Alpha build is more of a debug build and has not been optimized yet. It could cause some problems with large pages on low memory devices like the Droid. Issues like the app exit and relaunch on first start, as well as on add-on installs might come your way. To fix the installation process the team is actively working on it.
Currently, you can’t open links from other apps using Fennec but will be addressed in the next build. Before installing Mozilla Fennec on android make sure that your phone is running Android 2.0 or above, and likely an OpenGL ES 2.0 capable device. It is also important to note that Mozilla Fennec Pre-Alpha build must be installed to internal memory and not to a SD card.
Download Mozilla Fennec Pre-Alpha for Android Phone
Mozilla Fennec Pre-Alpha Android version