I wouldn't suggest trying to unlock it yourself, give it to a store.
When I got mine unlocked it only costed $30 Canadian and it only takes like 20 minutes for them to do it.
Like youcell said, Bell and Telus don't use
SIM cards, they program it into your phone, so unlocking it for them wouldn't work, just wait for your contract to end then sign a new one with Telus or Bell, but be careful, telus and bell programs your number into the phone, and that can turn out to be a real pain.