Hide and Show the Dock in Mac OS X
The Dock is one of those staple features of Mac OS X, it’s popular and intuitive enough for it to be a core UI element in iOS, and for Windows to take a variation of it into Vista and Win7 (Android and Ubuntu too for that matter).
Hide and show the Dock with a keyboard shortcut
If you hit Command+Option+D it will automatically hide or show the Dock. If you choose to hide it this way, it will reappear back if you hover over the region that you have your Dock placed.
Automatically hide the Dock when not in use
You can set the Dock to automatically hide itself when it’s not being used by either hitting the Command+Option+D shortcut as mentioned above, or by enabling the option in the System Preferences -> Dock -> “Automatically hide and show the Dock” by clicking the checkbox next to it. This is an underused but great feature.
Why hide the Dock?
I use the Dock constantly, combined with Spotlight it’s how I launch applications on my Mac. However, I find that having the Dock automatically hide itself when not in use saves me a fair amount of screen real estate on my MacBook Pro 13″ and this is particularly valuable with maximized applications and web browsing.
I suspect that come Mac OS X 10.7 we’ll see the Dock automatically hide itself by default when you enter into the upcoming full screen app mode.