For just a -2" you can also cut down the springs inside. Cut 1" or 1.5" off the spring and give that a shot. Careful, though, because if you cut off any more than an inch or so you'll end up bottoming the forks on hard bumps and that will give you a nasty wobble every time.

If you wanna do it yourself you'll have to have access to the large metric fine-thread tap for the inside of each tube. You have to cut them at the top, the bottom is too complicated. Cutting them is a piece of cake, but that tap is pretty special and I wouldn't know where to go to get one.

You can buy 2"unders at CycleX, I believe they keep them in stock, as long as they are the '73+ forks.