Part 1 of Geocaching with the iPhone
How to use Maps to find your cache

iCache Geocoin
Maps does not have any direct support with the geocaching.com site. Nor any support for paperless geocaching. But if you have your coordinates with you, you are not lost. Maps accept the following as a valid coordinate entry:
48 09.423 11 23.648 (which translates into N 48° 09.423′ and E 11° 23.648′)