Great advice Pullchord, and I'm impressed with the BeeGee's reference. Brilliant analogy with Etta James' voice.
I am a slide hack, but have played at it for decades. Warren Haynes is a master and even though he's steeped in classic/Duane style, he has a unique voice due (IMO) to his tendency to play in standard tuning. I'm not sure I'd recommend that if you're just starting out; you'll be struggling with the mechanics (damping, "fretting") so an open tuning will at least ease your pain a little.
There is a guy named John Tuggle that has free lessons at the Gibson site and also sells others on his own site
http://www.learningguitarnow.com/. Haven't tried it but the samples look very good.
When I started out I got an Arlen Roth book/tape and I'm sure there are videos out.
He is obsessed with damping with both hands, and I got very little out of it.
David Hamburger has a book/CD out that is cheap and very useful.
That said, get you some David Lindley, Ry Cooder, Duane Allman, John Mooney (oh yeah), Hound Dog Taylor CDs and start soaking it in.