How does it work?
You register with a geocaching website, say www.geocaching.com . Membership is free, but for a small monthly fee you can take out premium membership, which comes with additional benefits.

Having chosen a geocaching identity and a password, you provide some details about your home location. This enables Geocaching.com to display the coordinates of all the geocaches near your home location. You can also enter a zip or post code into a search box to display geocaches near that location; useful if you’re going on holiday or planning a day trip.

Now click on a geocache in the list to display its web page. This web page is created by the person who hid the geocache. It contains the coordinates of the geocache, a short description of the cache, an encrypted hint and other useful details, such as level of difficulty, size of cache or terrain. There is a converter to display the coordinates in other formats, and usually a .loc location file that can be loaded into some GPS units. This saves typing the coordinates into the device.

You load the coordinates into your GPS device, either by keying them in or by loading in the .loc file. You take a copy of the cache description and hints, either by printing out a paper copy of the web page or loading it into your personal digital assistant (PDA), and you head off to find the cache.

When you find a cache, you open the container, take a look at the contents, sign and date the log book and re-hide it, taking care that no non-geocachers or ‘muggles’ see you doing this. Usually, you may take some photos of the location or the experience. When you return, you go back to the geocaching website, access the cache web page and log your find. This ‘logged’ find appears against your geocaching identity. Many geocachers have logged thousands of finds.

You can also upload photos you’ve taken and you can leave a short paragraph describing your experiences of the geocache – funny encounters, surprises, the state of the cache if, say, it needs attention because it is deteriorating. Photos that give away the location are called ‘spoilers’. They are permitted, but they need to be noted as such so others do not accidentally see them and spoil their geocaching fun.

To get started, you can simply create and ID for yourselfe on geocaching.com (for free) and look up the geocaches nearest your home location and head off to find them. It's easiest with a GPS device.

Another form of virtual geocache is the earthcache. These are coordinated through the earthcaching website, which was created to provide an exciting way for geocachers to learn how the earth has been shaped by geological processes. Earthcaches are created by geocachers with knowledge about geosciences that they would like to share. All earthcaches are verified by the
Geological Society of America before they are posted on the website.