Birmingham, AL – Cell phone users in the nation's 100 most-populated metro areas can begin transferring home phone numbers to their cell phones today. They also will be allowed to keep their cell phone numbers when they switch wireless companies. The new telephone rules take effect today, and residents of Birmingham and Mobile are eligible to make the changes. A spokesperson for BellSouth says there's a possibility people in other areas of Alabama will also be allowed to participate. The rest of the nation will be able to take advantage of the new rules later.