If you are woried about getting an Apple iPhone on June 29th, there may be a solution. You can actually hire someone to wait in line for you for up to a day. Some are charging around $250, but it would gaurantee you a place in the line.
I am not sure this is really worth it unless you have lots of money just laying around, but then again you must to by the iPhone in the first place (well that or just be crazy like me). There are a couple more options for those of us that want it soon however.
There have been reports that each coporate AT+T store will have 300 iPhones. There has not been any confirmation of this, but it has been posted out there. Another idea is that AT+T will have a mail order option once the store runs out of iPhones in stock and they are supposed to ship within 3-5 days (unlikely in my opinion). I think most people should be able to get one on launch day that wants one as lnog as they are at the store at 6pm. Only time will tell.