Pligg is for sale. Though I mentioned before that we adopted Pligg on Rocketboom, we actually wound up adapting some of Pligg for Moveable Type, and forked off the rest.
Jamie got almost everything we needed so far into just a couple of pages.
I actually just started participating in Digg myself. Im slowly ramping up but I feel a major swing coming on. I think YouTube and Digg are my top two favorite websites on the internet right now.