Rockabilly Style

I vouch for the rockabilly bible, i got that one as well as the bass one and they are both awesome.

Another thing I would recommend that is definitly worth it is to check out http://www.riffinteractive.com and get their rockabilly legends lesson, i ordered it for a few bucks and teaches you some really neat styles.

also you may want to check out some pyschobilly bands and learn some of their songs, its got a darker creepier sound but a lot of the bands have really good guitarists. You will probably find a crapload more psychobilly bands now a days than you will rockabilly bands.

a lot of elvis tunes are good for starting rockabilly on too, thats what got me started on upright bass.