Reddit mentions of Adobe Photoshop CS5 Classroom in a Book

Adobe has some pretty good tutorials, if you're looking to learn a specific thing. Otherwise, basically just messing around with Photoshop helps a lot. Observing the changes that each tool makes sticks in your mind a lot better than being told exactly how to do something. Also, Nik Software has some good filters you can demo and/or buy. I use Color Efex Pro 4, and the skin softener might help you out a lot with your model shots. This book is pretty useful, if you have the time to work through it. I'm taking a class right now, but I honestly have learned more through messing around myself than what the teacher has specifically taught us.

adobe makes good books for their programs, Illustrator and Photoshop

This was a required book with my classes. It's pretty in-depth and gives a good overall starting point.

I come from a graphic/web design background as well (and am an okay programmer) and I can say even regular people DO know if something looks good or bad (on a subconscious level) - they simply don't typically understand WHY that is or HOW to express their feelings (this doesn't mean everyone's a design though - just that they can sense good/bad).

For programmers who lack zero creative "oomph," what I'd suggest is copying sites/apps that look good. How do you know if a site looks good? Look at the level of craft needed to make it. Visiting "Nike Better World" will immediately produce a completely different experience from Reebok's Website. It doesn't take a rocket scientist to determine the clever bits of the Nike site come from the way the elements work with each other - a trick that could be perfected whether they are professional, perfectly setup photographs or flat colored shapes (what I'm saying is great visual design most of the time can still be done without relying on great artwork/assets - great photos/artwork just improve upon what's there).

So, programmers who are really concerned with design, here's my advice: Learn Photoshop (Adobe Classroom in a Book or Lynda.com are great ways) and then look for sites that stress "award winning" website/application design and COPY THEM. Even if you copied the entire "feel" and "design" of the Nike website, I would still much rather visit that to learn about shoes than the boring Reebok site. And, at the same time, if I wanted to buy shoes, I'd much rather use Reebok's site than Nike's Better World.