I just read an interesting article on RIMarkable that reminded me about how easy it is to unlock BlackBerry devices on T-Mobile. I just purchased a BlackBerry 8900 on Amazon. Because the phone is sold with T-Mobile service – I can’t readily take another carrier’s SIM card (such as I might do if traveling overseas) unless I have my BlackBerry “unlocked” to accept another carrier’s SIM.
There are generally two ways to unlock. First, search eBay and pay someone for an unlock code. These can cost $10 to $20. However the second way is to do it yourself and call T-Mobile and ask for it. I just got off the phone with T-Mobile support who verified that so long as you are outside the 14 day remorse (return) period that you can request the “MEP” code which will allow you to unlock your BlackBerry so any GSM SIM card can be used. More instructions at RIMarkable below.