If you take a look at your App Store settings, you'll find some new options for Automatic Downloads. This new feature allows you have new purchases made on other devices automatically download to the device you're accessing the settings from.
For example, let's say I purchase 1password Pro, a universal application for iPhone and iPad on my iPhone. If I have Automatic Downloads for apps enable on my iPad, 1Password Pro will automatically download to my iPad over the air. This feature is available for music, apps, and book purchases.