If you have an iPhone 4S and don't plan on upgrading to the iPhone 5, T-Mobile would like to speak with you. The fourth largest mobile carrier in the U.S. has put in motion a new plan to lure iPhone users to its network.

Starting September 12, T-Mobile retail stores will have demo iPhone 4S models running on the company's HSPA+ network. The plan is to convince iPhone users that their phone would run much better on its high-speed network than any of the competition. If the customer agrees, T-Mobile will then unlock the iPhone and set it up on its network. Seeing as how T-Mobile's network is GSM-based, only customers on AT&T will be able to make the switch. 

[via BGR]