If you've had your service for 60 days or so you can usually get the unlock code from your carrier if you tell them you are going to be travelling out of the country.
Posted from my CrackBerry at wapforums.crackberry.com
Carriers give our unlock codes under different circumstances to certain customers.
Your other option is to contact an unlocking service such as mine, to unlock your phone for only $10 cdn. We can have your code back to you within an hour or 2 max