keyboard shortcuts

Here's a fairly complete list: http://support.apple.com/kb/ht1343

You can also see relevant shortcuts both for the system and for applications simply by opening the menus at the top of your screen, and seeing the symbols and key combinations to the right of the menu. That link I provided details what the symbols mean, but here they are again for quick reference:

⌘ Command key icon (Command key) - On some Apple keyboards, this key also has an Apple () logo

^ Control key icon (Control key)

⌥ Option or Alt key icon (Option key) - "Alt" may also appear on this key

⇧ Shift icon (Shift key)

⇪ Caps lock icon (Caps Lock) - Toggles Caps Lock on or off