Link love from 2011 CNPA Annual Meeting . . .
http://www.pixiq.com/
Jim Zuckerman has several articles on the site but the one he referenced on image stacking can be found here . . .
http://www.pixiq.com/article/eliminating-digital-noise
He also mentioned this site for upgrading Photoshop by supplying any “report card” . . .
http://www.academicsuperstore.com/
For interesting Photoshop effects . . .
http://www.flamingpear.com/
The link to his site is . . .
http://www.jimzuckerman.com/
From Les Saucier . . .
http://www.lenstips.com/
His site . . .
http://www.appalachianjourney.com/
I don’t remember who shared this site . . .
http://thelightroomlab.com/