Paperless geocaching refers to the use of a PDA, smartphone, advanced GPSr, or other mobile device to access cache information in the field, rather than using pages printed from the web site.
To get the information into your mobile device, you need to download one or more GPX files, which have cache information including coordinates, difficulty and terrain ratings, size, description, and hint.
There are two main methods for paperless caching. The first method involves running a database program (such as CacheMate) on your mobile device that imports your GPX file and allows you to view and edit data about the caches.
The second method involves converting your gpx file into an ebook and then viewing the ebook on your mobile device. Common ebook formats include HTML, PDF, and Mobipocket (.mobi).
If you take up paperless caching, make sure you keep the information in your mobile device updated. There is nothing quite so frustrating as looking fruitlessly for a cache that is in both your GPSr and your mobile database and then finding out it went missing a few weeks earlier.
CacheMate is a program designed specifically for paperless geocaching, and is available for the Palm OS, Pocket PC, Windows Smartphone, and Google Android platforms.
GeoBeagle is a free, open source application for the Android platform to aid users in finding geocaches and letterboxes.
GeoShrine is a free program for java enabled mobile phones and PDA's. If the device has a GPS, then GeoShrine can make use of it, otherwise it can just be used as a cache reader.
Other software packages for the Windows Mobile platform includes: