Six Revisions: How to Make an HTML5 iPhone App.

This technique will also work with the iPad, and is a great way to get around the App Store if you're not a fan of it.

Related to this, the latest builds of VoodooPad (which will eventually become 4.3) have the ability to export a document as a "Mobile Web App". This spits out the document in a format that's compatible with the HTML5 offline stuff, which you can bookmark to your iPhone/iPad home screen and will automatically update itself when it notices that there are changes on the server.