If it is a GSM modem from RIM then it is probably a standard part.
It will needs a SIM card to connect to a network.
It will have the usual Hayes-compatible command set, and it will appear on some COM port number, say COM8 or whatever. If you start up a terminal emulator on the right port, and type in the 3 keystrokes
AT <enter>
you should get back
OK
and if you see that, you are in business.
I believe the AT commands will work even without a SIM card. Email me if you want to pursue this; I think I have some data sheets on RIM modems which used to be on their website but have been removed.
If you can get it working, you will have a laptop with GSM/GPRS and that is quite nice. "Every" laptop has wifi and even bluetooth but GSM/GPRS is a rarity. Together with wifi it gives you a very good mobile data platform; wifi can be hard to find but GPRS works just about everywhere.