XDAunlock allows you to remove the SIMlock from your Wallaby. SIMlock, sometimes also called SIDlock, is the wonderful mechanism that forces you to buy your cellular service from the same company that sold you the telephone. To use XDAunlock, first check to see if your Wallaby has a PPC 2002 ROM that supports the wireless modem feature. If it's Windows Mobile 2003 it's too new to run XDAunlock, if it has PPC2002 without the Wireless Modem application, it is too old.
The XDA-developers SpecialEditionROM comes with XDAunlock already on it. So if your device cannot run XDAunlock, you should consider installing it. (Even if you decide to go back to your old ROM right after. Use XDAtools to create a backup of your old ROM)
XDAunlock replaces our earlier tool XDAmanipulator for most purposes. XDAmanipulator may be useful if you need to reset call timers or change the IMEI on a Wallaby with a somewhat older RSU. XDAmanipulator only works if you have a serial cable.
To use XDAunlock, download using the link below, and tranfer XDAunlock.exe to any directory on your device using the 'Explore' funtion of ActiveSync. Run it and you will be prompted to ask if you really want to unlock, and then it's done.
Command line option '-q' will make it not display anything if the phone was already unlocked, otherwise it would display a dialog saying 'Your phone is already unlocked'. Starting up with '-l' followed by a space and an 8-digit code will lock the phone using that code, which is probably only useful for debugging purposes, or maybe for turning the device back in for warranty repairs. '-d' tells you the code, but there is no benefit in being told the code and unlocking it yourself: it's just as safe if you let XDAunlock do it.
http://wiki.xda-developers.com/uploads/XDAunlock.exe