Electric potential plays the similar role for charge that pressure does for fluids. It reflects the the speed and direction in that the free charged particle would move due electric forces caused by charge that create this potential.
The electric potential created by a point charge q, at a distance r from the charge, is equal to
where is the electric constant, a feature of the free space around the objects. This is also known as the Coulomb Potential. It is tied to the potential energy of the charged object in electric field, as described in , for instance.
The electric potential due to a system of point charges is equal to the sum of the point charges' individual potentials. This fact simplifies calculations significantly, since addition of potential (scalar) fields is much easier than addition of the electric (vector) fields.
Field applet by Carlo Barraco, Todd Fuller