Ok, I couldn't find a better forum to post this, so I choose this one. Problem is that I have an AT&T BlackBerry Pearl 8110 (w/GPS). It is unlocked for all GSM networks. So I received it today from the eBay seller. I popped in my T-Mobile SIM card and turned it on. It displayed invalid SIM card at the top. How is this possible? Is there a way to switch the network to T-Mobile? I tried scanning for networks, but it said the scan was aborted or something. Anyone purchase an AT&T BlackBerry 8110 unlocked but uses it with T-Mobile? If so, how did you get the phone to work?