Your Cell Phone's Been Crippled
To tether you to their service, carriers "lock" phones so you can't use them on a competitor's network. And sometimes carriers disable other features as well. But with a little time and effort (and spare change), you might be able to unlock your phone regardless of whether your carrier cooperates. Be aware, though, that doing so might invalidate your phone's warranty; read the fine print.
Why do carriers do this? Money. Service providers generally charge less for phones than third-party vendors do, and they need to recoup that money. So, for example, some carriers make it difficult for you to employ Bluetooth to let your phone act as a dial-up modem for a notebook or handheld (presumably to push you toward expensive over-the-air data services). Locked GSM phones also cost you money when traveling, as you can't swap out your SIM (Subscriber Identity Module, the tiny card that holds the phone number and other information specific to your handset) for one from a local carrier, which generally will charge less than most U.S. carriers do for overseas roaming.
The easiest and most common unlocking technique is to enter special numbers on the dial pad--typically an unlock code plus your handset's International Mobile Equipment Identifier (IMEI), Electronic Serial Number (ESN), or Master Subsidy Lock code (MSL). Some phones, including Samsung and Sony Ericsson models, you can unlock only by connecting them to a PC using special cables and software.
The safest way to get your unlock code is from your carrier. T-Mobile, for example, will provide codes 90 days after you subscribe. Cingular generally doesn't help customers unlock phones, but makes exceptions on a case-by-case basis, says spokesperson Ritch Blasi. Sprint won't unlock phones--period. (Verizon Wireless says its CDMA handsets are unlocked.)
If your carrier refuses to help, third parties will sell you unlock codes for about $30 and up; a Google search for "unlock phone" produces links to Bongo Wireless, GSM Locker, and Mobile Fun. Many of these outfits are Web-based, but independent brick-and-mortar shops are preferable because you can walk in and talk to a person if there's a problem. Whatever company you use, make sure it's legit: Find a contact number, and call a sales rep to get details such as cost and service guarantees. If the unlock code doesn't work, will you get your money back? What will the company do if the unlocking procedure breaks the phone?
A Google search will also lead you to forums and blogs where fellow cell phone users share unlocking secrets--for example, Howard Forums (registration required) and Treonauts, which provides unlocking tricks for Cingular's Palm Treo 650.
Some blog sites also help you circumvent restrictions on Bluetooth file transfers. For example, IrishEyes and RussellBeattie.com publish instructions on how to unleash some of the Bluetooth powers of Verizon's Motorola V710 handset.