I don't know, why would you even want to check it in the first place? Are you suspicious that she's doing something behind your back?
How can I get information from my girlfriend's mobile? I own the sim card, is there anything I can do to check it?
Have to say, phone=personal space, just ask her whatever it is you're wondering about. If you invade her privacy, she'll never forgive you and you'll not have a relationship anyway.....js