To help streamline your iPhone 3G S purchasing experience, AT&T has posted a brand new video on YouTube that outlines a couple of important iPhone launch day details.

Unlike the iPhone 3G launch, both AT&T and Apple are taking pre-orders for the iPhone 3G S.  You can pre-order an iPhone 3G S at Apple’s online store and have it shipped straight to your door for free on launch day, June 19th.  You can also pre-order an iPhone 3G S from AT&T’s online store and have it shipped to a retail store or to you.  If you choose to pre-order your iPhone 3G S in an AT&T retail store, you must pick it up at that same store.

Pre-ordering is definitely the way to go if you fully intend on purchasing an iPhone 3G S.  On launch day, two lines will form at 7 A.M. local time at all AT&T retail stores.  Customers who chose to pre-order will be able to pick up their new iPhone 3G S at that time on a first come, first serve basis.  Customers who didn’t pre-order will have to wait in line until the store opens at its regular time to get their mitts on one.

There are a few other new items worth noting.  AT&T will be selling off the rest of their 16GB iPhone 3G stock at $149 to qualified customers.  The iPhone 3G S, just like the iPhone 3G, will be available at a no-commitment price.  The no-commitment price for a 16GB iPhone 3G S is $599 and the 32GB iPhone 3G S is $699.  No-commitment pricing means that you are not under an AT&T contract, but just like the regular plans you must have a voice plan and data plan while you are using the iPhone with AT&T.

Embedded below is the AT&T iPhone 3G S launch day video.  Don’t mind the two-star rating that the video has received so far, people are just still upset with AT&T over the lack of MMS and tethering.

[Thanks to Odie for the tip!]