To get photoshop in fast track shortcut is very useful speed tool. In photoshop most of command can access though shortcut but only few that will regularly use in general for most of photoshop user and you should memorize it to speed up your work. In this list will cover all general use shortcuts you will have to use it most of time you open photoshop.

Since PhotoShop CS the shortcut are fully customized via menu Edit > Keyboard Shortcuts (alt+shift+ctrl+K) this is useful you to add your own special Shortcuts that you recently use. But for following shortcut that regularly use for most user. It's good idea for you should leave it as is, so you will not get an headache when you use other machine and this will save if other will use your. Otherwise you may have to save your own custom shortcut with you in your thumb drive.

This is the list of shortcuts for mac user should use Command key instead of Ctrl and delete instead of backspace. It's available in blanket ( ).

You can see complete list of photoshop tool and its overview at Photoshop CS3 Toolbox: Quick Reference