A friend has gone the reserve-at-a-store route.
He picked the store he wanted to pick it up at, and - with his Apple account - was able to reserve one. It doesn't appear that a credit card was specifically asked for (as it was when I ordered mine from the Apple Store) though many people do have a credit card attached to their Apple account.
He said that they told him he has until 3pm on Saturday to pick it up; after which that it will be released to the general public; so there's no grantee that there will be one available after 3p.m.
Now we are in a competition; will he get down to the store and pick his up before mine is delivered?
I hope he doesn't get a free goodie and I miss out :(
Meanwhile, Philip Elmer-DeWitt at Fortune estimates that Apple sold 50,000 iPads in two hours.