I am guessing the lines to pickup phones will start forming before the store opens, and if you are not in line early, you wont get one friday at all. Chances are better than average that the iphone will be sold out friday morning completely at almost all locations around the country.
if you have one on order, just wait for them to deliver it. if you wont be home ....arrange for them to hold it and then go pick it up from the delivery people.