What do you need?
A working Global Positioning System, that will let you enter in longitude and latitude coordinates to three decimals in the "minutes".
A free membership with www.geocaching.com.
A sharp pencil. (Each cache has a log. Sign it with the date and name for your pack.)
A pair of tweezers. (These are for retrieving "microcaches" - tiny caches with only a rolled up paper log jammed into cracks and holes.)
A bag of little toys and party favors. (For larger geocaches with tradable items.)
Eager Cub Scouts that like to find things.
A keen eye and a mind to explore.
Tips for geocaching with Cub Scouts:
1. Be prepared! Whether you are geocaching in the backwoods, or looking for urban geocaches, always follow the safety rules in the Guide to Safe Scouting. Know where you are going, including finding the geocache ahead of time to make sure it's still there. Know what the weather will be like. Know what size of geocache you'll be looking for. Know how to get there (car? walking? hiking?)
2. Larger caches are better for younger Cub Scouts. Large caches are more likely to have items available for trade - the rule is, if you take something out, leave something there of equal or greater value. Cubs love to find stuff to trade. Your bag of small toys and party favors can also be the "default" treasure bag if the items in the cache don't interest the boys.
3. Make sure your GPS has good batteries before you start out. If you can recruit some of the Cubs' parents to participate who have their own GPS units, then more Scouts can have a turn at holding one. The Cubs can easily turn nasty on each other over who gets to hold the GPS. The more units you can borrow, with supervising adults, the better.
4. Keep it short. Young Cub Scouts do not like "long walks to nowhere". For the first adventure, find a geocache and see if you can park less than a half mile away from it. You can gradually work them up to trips of a mile eventually if you pick the right caches in exciting looking places.
5. Look for other things while you walk - see how many different birds you can see (Wolf Elective 13), collect leaves, seeds, or shells for nature crafts later (Bear Elective 12) or pick up garbage as you go (Leave No Trace Awareness Award).
6. Don't forget snacks and a trash bag to pack out wrappers in!
7. Have fun!