Mozilla has just released an updated version of Firefox 4 Beta for Android and Maemo. Firefox 4 for Android is now available in the Android Market, which allows users to install Firefox on their Android devices directly from the market.
Install Firefox on Android
If you are using any (supported) Android device, visit this URL: market://details?id=org.mozilla.firefox to install Firefox from Android market. Alternatively, you can search for it the market (AppBrain page). Firefox 4 beta is supported only on selected devices (see list of tested handsets here), so you may not be able to install it on unsupported devices.