I don't really know if this works for RIMs but it doesn't say it wont...
The program is called Code Calculator. The current version is 5.4
I used it to unlock my Nokia 3650 TMO so my friend can use it on Cingular.
It worked like a charm.
It says Nokia but you have an option to pick different phones.
here is the URL http://www.unlockme.co.uk/dct4free.html