The Apple Store App which allows you to shop for apple products without visiting the site has been upadted to work better on iOS and iPhone 4.
Along with iOS 4 compatibility the app also adds high resolution images such as the icon.  The icon now looks super crisp as compared to before.  There are as always some small bug fixes.  Official Changelog below-
-  iOS 4.0 compatibility
-  High resolution product gallery images for iPhone 4
-  Various bug fixes and improvements