For several years, photographer and designer Trevor Morris has maintained a great set of Photoshop keyboard shortcut cheatsheets. We've linked to his collection several times for previous versions of Photoshop. If you've upgraded to Photoshop CS4, download this handy PDF cheatsheet, print it out, and keep it near your computer:
If you haven't upgraded to Photoshop CS4 yet, we've got you covered. Trevor keeps an archive of his previous cheatsheets all the way back to Photoshop 5. We've got links to his full archive past the jump.
Complete Photoshop Cheatsheet Collection.
Trevor keeps an archive of his previous cheatsheets all the way back to Photoshop 5. Although his collection is PC-only for older versions of Photoshop.
Photoshop 7: PC
Photoshop 6: PC
Photoshop 5: PC
Source: This tip seemed like an appropriate way to kick off the first week of our free, 10-week, worldwide, Photoshop course. Week 1 kicks off with an introduction to Photoshop CS4, with a focus on Interface, Tools, and Shortcuts. These cheatsheets are available at the Trevor Morris Photographics website.