Like TPeirce said...
My wife works at a Dental Office, She takes my old mags to work and leaves them in the waiting room. You could do the same, but tack a card on the cover with Club contact numbers on them. Something like:

"Interested in learning more about RC Airplanes? We have a local club right here in town! Call Joe-Bob-Jimmy-Wayne at ******* for more info!"

Another great way to get the word out is to find your local Boy Scout troup. The Scoutmasters are always looking for new ways to entertain the kids. Have three or four club members bring in a plane, and each can give a brief talk about how things work

IE One can talk about how moving a wing through the air generates lift. Another can explain engines and thrust, while another could go into control surfaces.

It's a rewarding experience for both the club and the scouts.