First check https://wiki.mozilla.org/Mobile/Platforms/Android#System_Requirements

If your phone is listed in the green list then use http://ftp.mozilla.org/pub/mobile/releases/4.0b4/android-r7/en-US/fennec-4.0b4.en-US.eabi-arm.apk If it does not work then there is a good chance your phone has an ARMv6 cpu.

If your phone is on the red list and is running Android 2.0+ then try the ARMv6 experimental build at https://wiki.mozilla.org/Mobile/Platforms/Android#ARMv6_.28experimental.29 there are no guarantees that this build will perform well.

sukhad, which phone are you using?

using a motorola xt720 running 2.2 Froyo !!!!

Moto has not provided it anywhere except Korea....I tweaked it, and flashed with RSDLite. Evrything is better than 2.1 I repeat every feature is better.....and camcorder/camera is mind-blowing !!!

App2SD, Adobe Flash Player, Call Blocking, etc all fetures absent in 2.1 Only 1 problem though, Motorola Batteries SUCK......no improvement in battery life...same as 2.1...but evrything else is too good....

Thanks kbrosnan, i installed Fennec nightly instead of firefox....no serious problems...and i bet it will be the best browser for andro in less than a year....

Image attached as proof of 2.2.1 install.....thx guys........