One of the best chapters about our beliefs in the after live comes from the Book of Alma Chapter 40 here is a link to that chapter:  
 
http://www.lds.org/scriptures/bofm/alma/40?lang=eng 
 
LDS believe that when you pass on your body returns to the Earth from which it was made and your spirit passes through the Veil of Forgetfullness that covered your memory of your life before mortality and you enter the spirit world.  
 
In the spirit world there is two sides paradise and prison. Paradise is for the righteous whom have faith in Christ and have accepted all the ordinances of salvation, theses persons are in a state of spiritual rest and are used to help bring the gospel to those whom never had a chance to hear it or accept it in this lifetime.  
 
Prison is where those whom are not righteous or have not accepted the ordinances of salvation they must remain here till either 1) they repent and accept the or dances of salvation done by proxy for them eventually in LDS temples or 2) the end of time after Christ's millennial reign and lucifer's final defeat.  
 
After this period all whom have lived will be judged and receive there final glory based upon there faith and there works in mortality and the pre and post existence.