Do I have to jailbreak my iphone to change service providers?

I have been using my iPhone 3GS with Bell but I would like to change to Koodo. Do I have to jailbreak it in order to unlock it or is there another way? I don't want to do anything illegal, simply change my service provider. Thanks.

You have to unlock it.

You need unlock it, check the trusted unlock guide:
http://www.monitoring-softwares.com/how-to-unlock-iphone.html

Jailbreak it is not illegal, but unlock is illegal you need read this
http://iphone.pandaapp.com/news/01282013/Come_on_Sign_the_Petition_to_Make_Unlocking_Cell_Phones_Legal.shtml