Padgadget.com has rated the official Geocaching App from Groundspeak as the number one app for summer fun! I have to totally agree with them! I love the Geocaching app and use it often, especially when I am away from home and don’t have the cache in the area I am in in mt Garmin 62ST.
You can geocache with just the iPhone but I prefer my dedicated handheld GPSr. With the Geocaching App you can find all the cache in the area you are in and you can even filter your searches by cache type, difficulty rating and terrain rating. You can also log your FIND or DID NOT FIND right from the app and log trackables.
You can download and install the Geocaching App for your iPhone or iPad HERE. It cost $9.99 but is well worth price. You can also get their FREE Introductory App but it only lets you see three Geocaches. Download the free app HERE.