That's an interesting idea. What sort of experience level are we looking at? Beginner, Intermediate, Advanced?
Though I'm not exactly sure about the pervasiveness of PhotoShop - you may be limiting your audience somewhat. I could be worthwhile discussing techniques in a more generic manner. Knowing how to perform a trick (click here, select that) is one thing, but fundamentally understanding a technique would be a more valuable proposition (to me anyways!
).
Love to hear more in due time!