The Apple Store app has received a nice upgrade, adding several new features and international support for customers in Canada and China.
One extremely nice feature is a personal pickup option, something I've used at Best Buy at times. Buy a product through the app and arrange for pickup at the Apple Store of your choice within an hour, depending upon stock availability. For those in a hurry, this will greatly cut down on the time and the hassle of fighting through the throngs of customers in a crowded Apple Store to grab something quickly.
EasyPay is something that I'm really eager to see in action, and if the closest Apple Store wasn't 45 minutes away, I'd be off to try it this morning. You can purchase select accessories at the Apple Store by scanning the barcode with your iPhone or iPod touch (or iPad, but that's probably a bit unwieldy) and complete the transaction from the app without having to go through a store employee.
The app store description doesn't tell you what to do after you use EasyPay. Your receipts are stored on the iPhone, so if you're challenged to show your proof of purchase by a store employee on the way out, you'll be able to demonstrate that you're not walking away with merchandise. It will be interesting to see how the Apple Stores adjust their security approach, if at all.
Both the personal pickup and EasyPay features are U.S. only at this time, and EasyPay requires an iPhone 4 or iPhone 4S.