iOS Updates to Come Over WiFi and 3G

One of the new features of iOS 5 is the ability to update your iOS device without a computer. This means you can download updates wirelessly. Through searching through the latest SDK developers have found support for over the air updates on 3G as well as WiFi. It's uncertain how large the updates could be over 3G, especially since many carriers have data caps. A person's iPhone will only download the update if there's enough disk space and battery life available to download and install the update.
via Gizmodo