Tony played a south-paw Gibson SG into a Dallas Rangemaster treble booster, then into cranked 100-watt Laney heads.
In the studio, one of his trademark techniques was to double his guitar lines, including solos, to thicken his tone. Often times, he'd slightly vary what he played in a given solo so that most of it sounds perfectly doubled, but every now and again you'd hear one thing in the left and something slightly different in the right.
His guitars were always tuned down a half-step or more.
He also sold his soul for rock 'n' roll.
- Keith
P.S. This is the website Rainmaker posted but didn't come through all that well:
http://www.dinosaurrockguitar.com/bios/Iommi.shtml