From RCR:

The GSM Association (GSMA) announced plans to upgrade the system they use to track stolen GSM cell phones. Each GSM phone has a unique IMEI number (akin to a NIC card’s MAC address.)

When carriers get a report of a stolen phone, they can feed the information into this DB, which is available to all other carriers. They can then deny service to a phone which has been blacklisted.

Pretty much all cell phone makers support the plan and teh system. On the thieves side are LG Electronics and Samsung Electronics.

If you plan to get a GSM phone, go with another carrier listed in the article. That way we can help put a stop to theft of phones. There’s no incentive to steal a phone that can’t be used or sold…