I was at my local Barnes & Noble today & happened by the impressive array of photoshop books. It made me wish that there was a book explaining how to use paint.net. I use it pretty infrequently & seem to always have to re-learn stuff every time.
Someone w/more energy than me should package up some of the tutorials and publish them, and maybe donate a portion of the proceeds to the paint.net team...
Just a thought.
Cheers,
-Roy