There is a site that I will refer you two called Chordhouse.

Address is http://www.looknohands.com/chordhous.../index_rb.html.

It allow you to pick your tuning - Open E, Open G, Drop D, standard whatever then pick your major, minor or whatever chord and it will be laid ot on the fretboard ( first 12 frets). What you have to do it then look for pairing or grouping of three strings for Triads up and down the neck for chords. I play open E so I refer there to find chord patterns. Same will hold true for Open G.

What works best for me in learning songs is listening to the cd and having a tab to refer to. I did Kirk's dittie in drop d yesterday and got most of it figured out. At one point I had to stop watching his hands and listen but he did have the pattern laid out. The leads I sorta got close to in the middle section but my timing on the end was off.

I will check my archive and see if I have any open G stuff for you.
Cheers