You might want to check out the beginners section of http://www.wattflyer.com
RCU owns the site and it is dedicated to electric flight.

Horizon Hobby http://www.horizonhobby.com is the US distributor for E-Flite, Hobbyzone, Parkzone, and probably others.

You can see the offerings from Hobbico, Great Planes, ElectriFly, FlyZone, Goldberg, and others at http://www.towerhobbies.com

Hobby-Lobby http://www.hobby-lobby.com/index2.htm (not the arts and crafts store) also sells a lot of electrics

You can order online or buy locally. The web sites make it easy to see a lot of stuff because few local shops would ever be able to stock so many different things.