I watched Mr. Haynes very carefully to figure this one out with this 
You can see in the beginning he is tuning his gutar down. Thanks MyInnerEyeMike.

      intro                                                 main verse
eb:---------------------------|--------------------------------------------|
Bb:---------------------------|--------------------------------------------|
F#:--12-x-12-x-12---12-12-12--|-----2------2---------------2------2--------|x4
C#:--12-x-12-x-12---12-12-12--|-----2------2---------------2------2--------|
Ab:--10-x-10-x-10---10-10-10--|-3p0----3p0-----3p0h5p0h3p0----3p0----------|
Eb:---------------------------|--------------------------------------------|

 first chord break after verse x3  then  to  --->   second chord break (oooohhhh hhhhhoooo)
eb:-----2----3-----------|--------------------------------------------------|
Bb:-----3----3-----------|--------11----------------------------------------|
F#:-----2----2-----------|--------9-----------------------------------------|
C#:----------------------|--------x------5----------------------------------|
Ab:----------------------|--------7------5----------------------------------|
Eb:----------------------|--------9------3----------------------------------|

The solo varies every time they play it so i couldn't really tab it out (sorry) but you 
just improv using the penatonic scale seeing how it is really a blues song.