The Photoshop: Mastering Advanced Techniques class covers a lot of really creative tools in Photoshop, like 3D modeling, Smart Objects, and 32-bit color space. After this course, you should know how to manage sophisticated layers, merge 3D layers, and much more.
The Photoshop Basic & Advanced Skills package offers a great overview of Photoshop as a whole -- tools, palettes, menu bars, etc. You'll learn all about editing, composing, drawing, and painting, which makes for a well-rounded foundation in this design software.
The Digital Photography and Photoshop master series bridges the gap between taking great digital photos with your DSLR camera and editing them with Photoshop software. Learn all about photography basics -- natural light, composition, exposure, etc. -- with some helpful hints on using Photoshop to enhance those snapshots afterward, too.