Slowhand Blues Guitar
12bar.de offers free blues guitar tutorial. You'll find lots of tutorial on guitar chords, blues rhythm, scales, techniques, fingerstyle and many more. There is also a community forum that you can sign up and discuss about learning blues guitar. The most interesting part of the site is the blues guitar chord and scale generator with fretboard scheme. The scheme does looks complicated with lots of option to choose. Luck that instructions are available to get a good start.