Since today one of the main features of a geocaching app is ready: offline maps!
You can create offline maps with programs like Mobile Atlas Creator (MOBAC) from different mapping providers, including OpenStreetMap. This maps you can transfer with iTunes to Looking4Cache. So there is no need for a 3G connection while caching.
Also it should be possible to use a iPod touch (from 2nd generation, because of gps via bluetooth) to find the caches.
The iPad version is ready since some days. Today i finished the iPhone version.
Outstanding some small improvements and the legal communication with Groundspeak and Apple. Release Date comes closer!
Looking4Cache is a Geocaching App with a large set of functions. Offline usage, different map providers, API connection to geocaching.com including search and logs and trackable handling.