AT&T now offers the same online pre-buy as Apple for the iPhone, so you'll theoretically have to spend less time at the store. Entering your billing info will take care of the credit check, and if you're coming from another carrier, you can see if you're eligible to port your number.
Existing AT&T customers can scope out if they're eligible to add a new line for the iPhone. It'd be nice if you could go all the way and cut out the trip to the store entirely, but that's probably not going to happen.