Beginner music theory for guitar

[9e0r9e]

Hi all, I have been playing guitar for about a year now, pretty much self taught. Being a poor student I can't really afford to pay for lessons. However i've been making decent progress mainly through watching videos by Justin Sandercoe and Marty Schwarz on youtube, both of whom i would highly recommend. I know all of the basic open chords now and am relatively comfortable with barre chords. My guitar playing has pretty much consisted of learning to strum along to my favourite songs (the easy ones anyway)

Anyway, now the summer holidays have come around and i find myself with a lot of free time on my hands I am wanting to learn some music theory. I come from a very non-musical background so would need to start at the very beginning. I want to understand things like keys and scales, arpeggios and why and how different chords are formed and named as such. I'm also curious as to why there are no b sharp and e sharp notes etc. Basically i want to broaden my knowledge of music in general and understand why i'm doing what i'm doing, rather than just putting my fingers in certain places.

Justin Sandercoe has a practical musical theory book that looks good, think i might purchase that. But does anyone know of any better learning resources, books, websites that might be useful to me. I have heard that it might help me understand theory better to learn the piano/keyboard alongside the guitar, i have access to a keyboard as well if this helps? I realise that there is no real substitute to a good music teacher, however due to my current circumstances this unfortunately isn't an option.

Thank-you in advance for any help that you may give me.

[singlecoil]

The Wikipedia page on music theory would be a good starting point, if you read and understand all of that you will be halfway there.

[timbob]

I've directed some of my students to the My Music Theory webpage before, who have found it useful. Here's a direct link to their Grade 1 lessons section:

http://www.mymusictheory.com/grade-1-contents/less...

[Nom de ploom]

I think I'll give that a go actually...

if you google "A minor pentatonic" for example there are alot of sites out there with fret boards that give you Root and scale diagrams. I find these help ful.

Mapping chords and then playing notes over them only comes with practice...