new to iPhone 4

Hello folks, I'm new to the iPhone 4, and I'm having a little issue I'm hoping someone can help me fix it, i don't know why but under the my info in contacts, when i go into settings/ mail-contacts-calendar, then under contacts, and my info my sisters name is showing instead of mine,this is my phone and I'm not sure how this happen, is there a way to fix it?

Thank you

I just realized i posted in the wrong section.

Go to Settings - Mail, Contacts, Calendars
Scroll down to the Contacts section, touch 'My Info' and it'll bring up the contacts list.
Select your own contact details

If you have been using your sister's Mac to sync, it will think the phone belongs to her as well and put her info on.

Cheers

Hugh