Some supported phones are not displaying Firefox in the Market for some reason. We're still investigating this. You can check if your phone is supported here:

https://wiki.mozilla.org/Mobile/Platforms/Android

and then download the app directly from here:

http://ftp.mozilla.org/pub/mozilla.org/mobile/releases/4.0b3/android-r7/multi/

(Note: If your phone is from AT&T, you will have to search for instructions on "sideloading" the APK file, since AT&T disables the option to install from non-Market sources.)

Thanks very much for the prompt and helpful reply. My phone is supported, and I was able to download the beta version of Firefox, which I'm now using. Great!

Just one question:

I noted the following on the wiki page about a known bug that applies to my situation:

"Fennec's JIT compiler is disabled on Samsung Galaxy S phones running Android 2.1 because of a bug in their 2.1 kernel, making Fennec slower than on other devices. Galaxy S phones already running Android 2.2 "Froyo" are not affected."

Is this anything I should worry about? Is it just a question of speed, or will I run into other problems? And once the bug is fixed, will I be able to upload a patch or will I need to uninstall the present version and install the new one?

Thanks again.

The JIT issue only affects speed. When your phone is updated to Android 2.2, Firefox will automatically re-enable its JIT. When new versions of Firefox become available, you should be notified through the Market (or you can download them from the Mozilla site if the problem with the Market isn't fixed yet).

Got it. Thanks again.

This problem appears to be related to the fairly recent Android Market app update and we continue to investigate the cause. If you go to Settings/Applications/Market and choose Uninstall you can uninstall the update and then you should be able to search for and install Firefox from the marketplace.

i can't install to my sony ericsson xperia 8 ?

Firefox beta 4 is available for android. A very good explorer and really fast. Try it below http://www.freemobifun.com/download-firefox-beta-7-0-beta-4-for-android/