It's now a lot easier to shop in Apple's online store via your iPad thanks to Apple's new free app Apple Store for iPad. It does a good job of using the larger screen space of the iPad to enhance your shopping experience, while having some useful features.
You can view the latest products that are trending and use gestures to get a variety of views. If you pinch together, for example, you get a view that just shows a grid of product photos. If you zoom in, then you see the text describing the products' details. Once you've purchased a product, you can pick it up at a nearby Apple Store or have it shipped to you. There's also a maps feature that lets you find a store near you, gives you directions, and lets you check product availability. You can also make Genius bar reservations or sign up for workshops or other events.