Mormonism and Classical Christianity share many similar tenets... so what sets us apart beyond relatively trifling matters such as eternal marriage, baptisms for the dead, etc? I believe that it can be found in this quote:
God himself was once as we are now, and is an exalted man, and sits enthroned in yonder heavens! . . . I am going to tell you how God came to be God. We have imagined and supposed that God was God from all eternity. I will refute that idea, and take away the veil, so that you may see. . . . He was once a man like us; yea that God himself, the Father dwelt on an earth, the same as Jesus Christ himself did. (Joseph Smith, Teachings of the Prophet Joseph Smith)
Aha! So, LDS doctrine states that God did not exist from the beginning of eternity. I believe that God has existed from all time in the same form He exists in now.
Well that clears that up :)