No, rooting is entirely different to 'unlocking' your phone. Rooting allows you to fully access the phone's read/write commands (security settings), so you can change the ROM and firmware of the phone. This won't allow you to unlock your phone from a particular provider, even if you change the provider ROM to a stock or custom ROM. Unlocking requires a specific code that's unique to each phone, rather than the generic process involved in rooting.