To get AROS onto the Palm you need a special program that uploads it into memory... I believe that one developer was able to jump to the AROS Kickstart in the Palm Memory and let it take over the device.
I believe there are special ROM flashing programs that will allow you to put AROS on the Palm ROM...
As to how usable... well it runs... :-) It opens a window :-) we have a touch screen device driver... but it doesn't really do much and no one is activly working on it at this moment in time...
I hope one of the devs who worked on it will post here :-)