The current jQTouch beta features image preloading, callback events, swipe detection, and extensions.
From the description:
A jQuery plugin for mobile web development on the iPhone,
iPod Touch, and other forward-thinking devices.
The demos look fantastic. I suggest trying them out on your iPhone, it’s worth the few minutes, especially for the animations. And, although web apps will never be on par with native apps, this proves how close they can get. I’m sure there are a lot of apps that could be built using jQTouch rather than going through the App Store.
Unfortunately there will never be a drop-dead simple commerce solution for web apps.