An Apple source has informed Ars that the iPhone's Safari is getting offline storage capabilities, a la Google Gears, which could be used to cache apps and data. There's also talk of possible icons on the home page that open up Safari-driven apps. But no third party development kit is planned for native programs. Ars also quotes their source, showing internal conflict of interest at Apple, regarding the limitations of AJAX and web-based apps: "You can't write [bleep]ing [bleep] in that." You know how we feel about this. [Ars]
I'm not so sure that a web-based SDK is really going to satisfy that many users. I mean, what if some users want a different browser? What is the point of emphasizing the OS on-board if one cannot properly develop applications to run on it natively?
Offline application support is definitely a plus, but it seems that it could just go so much further than this.