[Lester B. Flat]

I would first recommend you start listening to old jazz records, and it does'nt have to be guitar players. Louis Armstrong, Miles Davis, John Coltrane, Thelonius Monk, Charlie Parker. You have to learn the language. The instrument you play is secondary to the jazz concept of improvisation. Since you are classically trained you are probably bored with the limited harmonies used in most rock music and may be somewhat constrained by "the rules" of music.
But also, your classical training is a big advantage over someone like me who was brought up on rock&roll and never learned to read music. Whether you read or not, you have to have ears and a free spirit to play jazz because what is written is only the skeleton, and the flesh and blood is improvised.
Blues is related to jazz because although it is very simple harmonically, it is also very improvisational.
When you say you want to learn to play "jazz guitar", you should be saying, "I want to learn to play jazz". Catch my drift?
One last thought. Jazz is an entire universe. There are many different styles of jazz that are so diverse that it seems strange to label them as one, but what bonds them together is the freedom allowed in the expression. I'm guessing you have learned discipline, now you have to learn to use that discipline to experience total freedom. It's a spiritual journey. Embark, my son.

 

[Lester B. Flat]

I don't know what's available at iTunes. There are probably some contemporary artists there but they may not have the old masters. If you're a guitarist you have to listen to Django Rheinhart. He is revered by many jazz guitarists. Some of the other greats did'nt record under their own names so you'll find them playing with singers or horn players. An example, Herb Ellis played for years with Ella Fitzgerald. There's Wes Montgomery, Joe Pass, etc.
In the 70's, fusion introduced John McLaughlin, Larry Coryell, John Abercrombie, Al DiMeola, Pat Metheny. The fusion genre was/is dominated by guitar players because it was a rock/jazz mix. Do a google search for jazz guitar and take it from there. I don't really know what style of jazz you may be into. You have to really dig to find the best music because it is rarely popular, but it's out there. There are tons of compilation CD's that will introduce you to different players before you go and buy one of their records.