The main screen on the Droid X is called theHome screen, but not everything you have
loaded on your phone can be displayed in just
one screen. There are actually seven Home
screens to choose from on the Droid.
To quickly browse and preview the various Home
screens, press and hold your finger on the dots
in the lower left or right corners of the
touchscreen. Then in the pop-up preview, touch
a preview image to instantly open that part of
the Home screen. Or, just touch anywhere else
on the touchscreen to make the preview images
go away.
Source :dummies