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.
Mozilla says about this latest release, "This release is the fastest performing Firefox 4 Beta for mobile yet. You will notice faster start-up, page load times and responsiveness to panning and zooming. Firefox 4 Beta for mobile also offers nearly 200 Firefox Add-ons. [...] JavaScript is much faster: almost 15% performance improvement in Beta 4 compared to Beta 3.". Firefox Mobile includes Firefox Sync, which is also available with the Firefox 4 beta desktop version.
Arpit you posted it too late. Firefox on android is already available in the android market for last few weeks. See this announcement by mozilla:
http://blog.mozilla.com/blog/2010/12/22/new-improved-and-easier-to-use-firefox-4-beta-for-android-and-maemo/
the new thing is an updated version beta 4.
@AndroidKid: thanks for your quick comment. I just noticed it. :)