Justin Taylor notes a number of features if you’re an iPhone user:
- You don’t need to be connected to wireless to use it (i.e., you can use it on airplanes, in North Dakota, etc.)
- With a simple tap you can see cross-references, footnotes, etc.
- You can search the ESV Bible
- You can take notes
- You can highlight passages
- You can easily email, Tweet, or (soon) Facebook passages
Just search for ESV in your app store.