Hi, Since I'm going to get an iphone 4 next week I am planning to sell my 3gs. Aside from doing a "restore all setting and content" is there anything else that I should do? Do I need to remove the SIM card as well? As I'll be selling to a stranger most likely, I want to make sure there is no chance any of my info could still be on the phone. When my new phone arrives and I activate it, there will be no way someone could still use my AT&T voice or data plan on the old one, right? Thanks for any suggestions, I'm new at this.