Google’s Vic Gundotra just demoed the offline access feature for mobile devices in MWC’09. A similar feature already exists for the desktop (suppiled by Google Gears). This time, the feature works using HTML5′s App Cache and Database standards.
As HTML5 will be an open standard, this feature, once available, will work in all devices that support HTML5. The Webkit engine of the iPhone is under heavy development, and it its latest beta versions include these Cache and Database capabilities as well. As it shares the same web engine, the Android will also benefit from this approach.