Has anyone taken the PADI Digital Underwater Photography course? If so did you find it to be useful or is it just a reiteration of the manual that came with your camera?
The big question is... how many people read the manual, and if they did, did they get anything out of it? I hate to say it, but I've owned an Oly D40, an Oly 8080, and Oly sp350 and a Canon G9, and I've read several pages of the manuals in total, certainly never the whole manual.
There's a certain percentage of people who learn by reading manuals, and a certain percentage that learn by trial and error, a certain percentage that learn by being shown, and a percentage that learn by a combination of two or more of the preceding.
I did take a semester of photography way back in the Welcome Back Kotter years in highschool (1975 or so), and that has helped a great deal with my photography. I'm thinking that's what the specialty courses boil down to... some basic photographic technique information that some people may or may not figure out on themselves. For me, I've found being shown is much more effective and efficient time-wise than figuring it out on my own. Your mileage may vary depending on what you already are familiar with.
In the end, little beats practice, practice, practice.