I recently changed jobs and with the new job came a new benefit. The new benefit was that my employer paid for my cell phone since I would be using it a lot for business purposes. However, they wanted me to use their carrier. Wanting to keep my iPhone, I decided to find out how to unlock iphone 3gs. I needed to jailbreak my phone first, so that I could then unlock it. Unlocking your iPhone allows you to use other service providers.