Unfortunatly as far as my research as shown, the ONLY way to unlock a BB is to pay for it :( as it requires special software or something blah. Anyway, Bongowireless does it for 130CAN 100USD. Unfortunatly the only way is to pay :(
Actually there would be 2 ;) T-Mobile (which locks by default, but unlocks after 6 months of good service) and Cingular (which never locks any of their devices). I don't know why, however rumor has it, now that the subsidy law was passed in CA, that it will soon become nationwide, and no more subsidy lock *cheers*, however the bad news is, prices will go up higher :(
Actually were you aware that all Tri-Band/Quad Band phones from Cingular wireless come unlocked these days? Yup so you dont actually have to deal with waiting 60-90 days and actually wait for an unlock code...
One possible reason for cingular being more generous than most of the other carriers is that their international roaming is fairly poor so they are simply letting you use the extra bands on the phone you have bought.