Weather

• DTC Duats
• CSC Duat
  
• National Weather Service
  
• Weather Underground

Flight Planning

• AOPA Flight Planner
• NACO Online
• AirNav.com
• Flightplan.com

Government

• Federal Aviation Administration
• FAA Safety Team
• NASA
• NOAA

Organizations

• Aircraft Owners and Pilots Association
• California Pilots Association
• Cessna Pilots Association
• Civil Air Patrol