Watch the Open E Tuning online guitar lesson by Sonny Landreth from Slide Supernatural
Open E tuning or what used to be called Vestapol is basically the same as tuning the guitar to a standard open E chord. It's the same as open D just everything is up a whole step, so all the octave ideas are the same. Something interesting to note with open tunings and using a slide, since in this case the guitar is tuned to an E chord, if we barre at the 5th fret we get a A chord, and the 7th fret will give us a B chord. We can work through a blues pretty easily this way. The I chord is the open strings and the IV and V chords are on the 5th and 7th frets. I write a lot in open E as I like the harmonics it produces and it matches my voice well. As you can hear, the difference between D and E tuning may just be a whole step but sonically they are quite different.