PhoneGap and Titanium allow you build native iPhone Apps based on HTML and JavaScript.
Has anyone gained experience with both? What are the differences?
Unfortunately Titanium is not opensource anymore. You can develop apps freely but You have to buy Indie account to publish an app to appstore which cost some money.
PhoneGap is a free and open source framework that allows you to create mobile apps using web APIs for any platforms (iOS, android,windows, Blackberry etc) you think of.