I sell on ebay so I have a paypal debit card. I love to use it on several occasions for large purchases. I want to use it to pre-order the iPhone 4 through Apple. I have already transferred the funds to my paypal account, and that's why I love using it because I know the money will be there. I don't worry about spending it on accident if it's not in my bank account. The paypal debit card has a mastercard logo on it so I don't see why it would be a problem, but I see several people posting that At&t will not let you use a debit card. I was also wondering if I order through Apple, will I get the phone on the 24th if I order on the 15th and have it shipped to the store? When is Apple release date for walk ins? I have my reasons for wanting it shipped to the Apple store instead of my home.