Actually nearly every iPhone application I have works just fine without a network connection.

Having said that there are some (OK, lots and lots) that are designed to use the internet and all of those do require a network connection for full (or in some cases, any) functionality. Similar functionality from any device would also require a network connection of some sort. This list would include the streaming audio stuff like scanners or music, and anything that needs to pull stuff from a central data source, like weather apps or airline flight tracking. Lots of cool stuff but hardly 90% of the available iPhone apps.

- Eric