Spacecraft Avionics  
   Tutorial describing spacecraft avionics theory, applications and possible architectures.
   http://www.spaceavionics.com/

Aircraft Electronics Association  
   International organization of avionics and instrument facilities working with manufacturers, government and air carriers to promote standardization and increased efficiency within the aviation electronics industry.
   http://www.aea.net/

Professor Thomas D. Inman  
   Assistant Professor of avionics at the Pennsylvania College of Technology. Includes some course notes.
   http://www2.pct.edu/homepage/staff/tinman/

The Forum Bluecoat  
   Discussion and email list about the integration of modern avionics in the cockpit. Contact information, articles, reports, events and links.
   http://www.bluecoat.org/