Replacing windows mobile with android os

If it's possible you can't just install it. First you need to find an android setup that will install on the chipset that's in the axim. Then you need to find out how all of the functions of the phone will interact with the OS, if it will even see them all properly.

Here is a couple of links that may help you, these guys used the same chipset as what's in your PDA http://nemustech.blogspot.com/2007/12/android-porting-to-real-target-hw.html

http://androidcommunity.com/forums/f8/android-os-running-on-sharp-zaurus-pda-128/

http://hsc.com/Portals/0/Uploads/Articles/Android-Porting-on-Embedded-Platform_v2_0633850602027036930.pdf

Keep in mind this will run very very slow on that device.