The dock in Mac OS X Lion has various application shortcuts and by default it is positioned at the bottom of the screen. Mac users can quickly use these shortcuts to launch their apps from Dock.
Change dock position
Users can change the dock position using the option provided as part of Apple menu. Dock can be moved to either Left or right or to the Bottom of the screen.
Increase Mac screen space
If you want to increase the screen space of your mac system then you can turn on auto hide feature of dock. By this way the dock would be automatically hidden or displayed in the screen. You can turn on the this feature either by the using the option available as part of Dock menu or the Doc Preferences.