The major heresy of Mormonism is summed up in its central theological axiom, the doctrine of the law of eternal progression. To believe in and teach this doctrine is to be so separated from Christian orthodoxy that the unrepentant adherent is consigned to a Christless eternity. It is stated as follows:
As man is, God once was,
and as god is, man may become.
Roll that through your mind a time or two. This all starts with the LDS teaching that there are great numbers of planets scattered througout the vastness of outer space which are ruled by countless exalted men-gods who once were human like us. This may sound like Battlestar Galactica to the average person, but upon this axiom is base the entire theology of Mormonism: from the temple rituals for the living to those for their dead; from the teaching that families are forever to the pressure on parents to send theri youth to the mission field across the world.

The Mormon people are committed to a controlled program that maps out their entire lives as they seek their own exaltation and godhood, their own planet to rule and reign over.
http://mrclm.blogspot.com/2005/08/mormon-heresy.html