If you go to this site and enter your serial number, it will tell you when your warranty coverage ends. Subtract 1 year from that date and you should be at the date you purchased the iPhone, provided it was registered at the time of sale. https://selfsolve.apple.com/agreementWarrantyDynamic.do
Thank you. Since I am apparently out of warranty, it does not show the date. I got my iPhone 5 right when they came out, I remember that it took ATT about a month to make delivery even after it was all paid for. Do you remember when they first came out?