It didn't take that long to accomplish, surprisingly. Entourage posted the source code for the Edge on Friday. By Saturday afternoon developers at Android Police figured out how to root the Edge. For full details visit Android Police.
So why is it important? For the average user, it really doesn't matter. But this is an important step for developers. Now they can devlop their own firmware for the Edge and now it's possible for someone to (illegally) port the Android Market to the Edge.