Don't forget Scrappers Guide especially for the more advanced Photoshop Digiscrapper or aspiring designer.
http://www.scrappersguide.com
Premier membership gets you the best bang for your buck with Linda Sattgast.
And a new site with some helpful tuts for beginning digiscrappers is at Digital Design Den
http://www.digitaldesignden.com
I also really like the tuts and style of the
Photoshop Roadmap at:
http://www.photoshoproadmap.com if you're a photoshopper just learning the program, and endorse and recommend
PET http://www.photoshopelementsuser.com