-I am taking the commercial photography course at New York Institute of Photography and they just began giving a course in Digital Photography of which (from what I saw of the course structure) is over 60% about Photoshop. https://www.nyip.com/dpc/

-Google "Russell Brown" for some nice Photo Shop stuff.

-If you are near an urban area, check out adult education community schools. Many in our area now offer such courses in reasonably priced evening schools.