OpenCaching is a free application that turns your Android device or iPhone into a geocache tool complete with maps, log book, and cache logger.
Download the app to your Android device or iPhone, fire it up, and you’re ready to start locating and placing geocaches.
The app uses your devices GPS to locate local caches which you can then filter based on difficult, terrain, and type. When you find them you can log them directly in the app, update social networks with your finds, and mark the cache as a favorite on your personal geocaching map.
Hit up the links below to read more.
OpenCaching for Android
OpenCaching for iOS [via Addictive Tips]