Check out this meta app. It runs fully functional in an iPad (I’m told), and is a super fancy reference library for the iPhone OS.
It is a web app that you can see on any web browser but, when it senses that it is on an iPad, shifts into super-duper mode.
Here’s the links you need to pursue this technology:
The app on your web browser
Daring Fireball page
Dominion of the Bored page