Oh yeah, I almost forgot books!
Kalmbach publishes a VERY good book on airbrushing "How to Use an Airbrush" by Bob Downie (one of the best model painters to be found!). You should be able to get it from your local hobby shop (assuming you have one) or from a number of places online.
It's a great reference for airbrush use!
Also, there's a magazine out too. "Airbrush Action" caters to airbrush users, though not directly to modellers. Steve Boutte (another great painter) has has some stuff published by them, so they do cover models!
HTH,
Tim D.
http://modelcartech.com