I Just Purchased A Bb7250 From Ebay And It Was With Earthlink Can I Unlock It And Use It With Tmobile And How Do I Transfer Data From Sim Card To Bb

I think not. According to Blackberry this is a CDMA phone. If you are on Tmobile, you are on a GSM network. The CDMA carriers are Sprint and Verizon.

BlackBerry - BlackBerry 7250 Wireless Handheld Device | With Phone, Bluetooth, Email & GPS

any BB ending with 50 is CDMA
usually 00 or 20 are GSM

there are a few excepts to this but I cant remember what they are.

Wirelessly posted (Tmo's cheapest BB customer)

How about those ending in 30? The 8130 and 8330 are CDMA devices.

I couldn't remember the others.

I believe Earthlink was using CDMA for their BlackBerry service. Their devices would be incompatible with T-Mobile or AT&T. And neither Sprint or Verizon will allow you to register a device on their network if it was not originally sold by them. You might be able to flash one of these older Earthlink BB's to Cricket, but that's about all I can think of.

Do not try to apply any logic or reasoning to the numbering conventions before the 8800!

The 7250 and 7750 were CDMA
The 7210, 7230, 7280 and 7290 were GSM
The 7270 was a SIP based WiFi only device

The 7510 and 7520 were iDen

CLEAR AS MUD.