Where do I start?

[Senna1]

I'm going to add another plug for JustinGuitar (I'm currently using it to teach myself, in fact). Having played piano for almost a decade as a teen, I'm fortunate to have the basics of theory lurking somewhere in the back of my head, but Justin's beginner course does an excellent job of introducing the theory in digestible bites, once you're able to deal with open chords and the very basics (I believe it's Stage 5, where he introduces the note circle, on).