From Reuters:
Customers attempting to reserve the next iPhone were thwarted by error messages on the websites of Apple and AT&T on Tuesday, the first day of pre-orders for the phone. AT&T, the iPhone’s exclusive operator, declined to comment, and Apple did not immediately respond to a questions about the technical problems that provoked complaints by customers in several cities across the United States, including Los Angeles, San Francisco and New York.
Ditto for me. I couldn’t get in all day.