T-mobile will provide you the unlock code if you tell them you'll be traveling out of the country. You need to have had active service for 90 days and you're account must be in good standing. They will also provide you with instructions. I had no problems getting my BB unlocked through them. If none of these apply there are places online that will get you an unlock code but may cost a bit. I'm not sure but I think removing the SIM lock will also allow you to use data as well. My first BB was an unlocked Cingular 7290 and T-Mobile's data plan worked fine. Hope this helps.
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If you're considering leaving TMo I'm assuming you've been there awhile and won't get charged an early termination fee ($200.) Just like the other poster said, tell them you're traveling out of the country.
Unlock codes are tied to your device and PIN / IMEI. I can provide proof that once unlocked, the DATA is unlocked as well. I had my 8320 unlocked 15 days after purchase (due to active military travel), but under normal circumstances they will do it only after 90 days, and if your account is in good standing.
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