Lots More Information

• How GPS Receivers Work
• How GPS Phones Work
• How Satellites Work
• How Location Tracking Works
• How Compasses Work
• How Urban Gaming Works
• How Maps Work
• How Metal Detectors Work

More Great Links 

• Buxley's Geocaching Waypoint
  
• Geocaching.com
  
• Geocacher University
  
• Groundspeak Forums
  
• Navicache.com
  

Sources

• "Development of a Final Policy on Geocaching in Protected Heritage Areas Managed by Parks Canada". Parks Canada.
  http://www.pc.gc.ca/docs/pc/poli/interim/geocaching_e.asp
• Geocache.com
  http://www.geocache.com
• Geocacher University
  http://www.geocacher-u.com
• Letterboxing.org
  http://www.letterboxing.org
• "Reference: GPS Scavenger Hunting," Portsmouth Police Department News Release, February 4, 2007.
  http://www.cityofportsmouth.com/POLICE/press020407.htm
• Sloan, Gene. "Philadelphia, other locales 'cache' in." USA Today. May 31, 2007.
  http://www.usatoday.com/travel/destinations/
  ­2007-05-31-geocaching_N.htm