I think the best thing we can all do is make sure we don't hype the iPhone to people. Sure, we can hype people on the iPhone starting July 12th, but we want to make sure we can all get the model we want on the 11th. Selfish, I know, but hell it's the iPhone 3G! I'm allowed to be selfish!
EDIT: Also, remember it's the summer holidays. Actually I'm not sure if it's the holidays in England, but schools are off in Scotland so a lot of people will be on holiday, and the kids who want iPhones and are off will have to wait til their parents get home from work before they can get their iPhone due to the 18+ requirement