Cambridge In Color Sean T. McHugh(CambridgeInColor.com) has some excellent Photoshop tutorials that are focused on photography. It’s not often that you see tutorials that are written with such dedication and eye for details. A good example is his curves tutorial, that explain beautifully how to use Photoshop curves tool, a tool that’s still a mystery for many beginners.
Don’t forget to check out Sean’s photo gallery which contains some excellent photography!