Ready to make the jump from crayons to Photoshop? No need to panic -- the internet is packed with resources to guide you through your first steps in the world of professional image and photo editing. TastyTuts' comprehensive 33-video tutorial is as good as it gets and comes complete with extensive course notes and other useful content.
Rather than just lecture you on the various tools and techniques available in Photoshop, the tutorial will take you through an actual project -- the creation of a book cover.
It's usually more convenient to watch the videos one at a time via YouTube, but if you just want to download everything, including course notes, assets and the tutorials themselves, ~250MB archives for Windows and Mac are available for download.
If you're not sure if it's the tutorial for you, I'd recommend grabbing the course outline. It's a 44-page PDF that goes through everything you'll learn and includes cheat sheets and other handy tips.