Lots of good advice here - lessons are a good idea, IMO, after you learn some basic open chords on your own. Lessons from a decent instructor will keep you from developing bad habits and will accelerate your learning.
One of the posts about learning barre chords and the pentatonic scale (sounds complicated here but it isn't) is great advice - i have been playing for a long time too and can't read a note of music but this is all the "theory" really needed for rock & blues.
2004 R1150 GSA
2005 MV Agusta F41000S