Much information can be found at the discussion forums:

R/C Groups Discussion

Parts recommended to complete our kits, including R/C transmitters, receivers, servos, speed controls, batteries, motors and propellers can be found at:

www.aeromicro.com
www.rcworldofplanes.net

Other flat foam planes, kits, plans, and information are presented at:

FoamyFactory Models - 3D Aerobatic Electric R/C Park Flyer Model Airplanes
3D Foamy - 3D Aerobatic Electric R/C Park Flyer Model Airplane
Fancy Foam Models - 3D electric foamy airplane kits
FLATFOAM.COM
Foamtastic Models
FOAMWING
Funplanes

For safer enjoyment of this hobby, join the Academy of Model Aeronautics, the world's largest sport aviation organization.

If you happen to have a foamy website, or know of one that is not listed here, please point it out to us. 

The more, the foamier!