This may have been posted somewhere already but there is a tool out there that allows you to easily check the availability of the iphone 5S in Apple retail stores. I used it this morning and managed to reserve a Gold 64GB model at my local Apple store. Picked it up this afternoon and the rep at the store asked me how many weeks I had been waiting on it to come in and when I told him that I reserved it this morning online and didn't wait at all he couldn't believe it. Link is posted below.
http://iphone-check.herokuapp.com
http://iphone-check.herokuapp.com