Edward,
Firstly it depends on whether or not your talking about commercial boneyards or military. Tucson area is your best bet for the military aircraft but the commercial ones are scattered around quite a bit. Kingman, Goodyear, Victorville are the big three although I shot a dead DC-10 at Macon (Middle Georgia Regional Airport) today and that just goes to show you can find stuff anywhere. Various small to medium size airports through the south have stored birds eg: Alabama, Arkansas, Florida (Opa Locka). A lot of these southern states also perform maintenance work or conversion work so there will almost certainly be metal around. I could probably tell you at least one airport per state that has retired or stored frames, but hop on the internet and check out some pics - it is more fun planning your trip that way
Cheers,
Scott.