For OS X Lion Apple took Expose, Dashboard and Spaces and rolled them all together into one feature called Mission Control.
Using a trackpad gesture or a keyboard shortcut, Mission Control presents you with a bird's eye view of your running applications. Arranged in a row along the top of the screen are all your open spaces. Hovering the mouse cursor in the top right corner causes a large plus sign to appear, click the plus sign to add a new space.
In the centre of the screen miniature windows of all running apps are displayed. They can be dragged to a new space, temporarily zoomed by hovering the mouse over and pressing the space bar or selected and brought to the front by clicking.
Depending on your preferences the left most space is designated for the widget Dashboard. Again, a simple trackpad gesture or keyboard shortcut will move left or right to the next available space.