How to Resize the Dock in Mac OS X Lion
The Dock appears at the bottom of your screen by default, providing quick access to your most-often-used applications, documents, and folders in Mac OS X Lion. If the default size of the OS X Lion Dock bugs you, you can make the Dock smaller and save yourself a lot of screen real estate. This space comes in especially handy when you add your own stuff to the Dock.
To shrink or enlarge the Dock (and its icons) without opening the Dock Preferences window, follow these steps:
Make the Sizer appear by moving your cursor over the dotted line that you find on the right side of the Dock.
Drag the Sizer down to make the Dock smaller, holding down the mouse button until you find the size you like.
The more you drag this control down, the smaller the Dock gets.
To enlarge the Dock again, just drag the Sizer back up.
You can even enlarge the Dock until it fills your screen from side to side.
By default, the Dock comes stocked with icons that Apple thinks you’ll need most frequently, but you can customize it to contain any icons that you choose.
Many users prefer to have the Dock on the left or right side of the screen instead of at the bottom. So if you're looking for change, try changing the location of your Dock.