I know of unlocking, but do not have extensive knowledge. Please forgive. Basically my girlfriend's android (T-Mobile) broke and since I got the iPhone 4 I have an unused 3G at my disposal. Can I let her use my old 3G by unlocking it and putting her SIM card in the 3G? Is it that easy? Or harder? Are there any risks involved on her end? Links for information would be appreciated, thank you!