[Edited by DarthParametric, 6/13/2008 4:43:26 AM]
when the fleet shows up you can order them to help the council or destroy the reapers. Destroy the reapers and you get the renegade ending. help the fleet and you get paragon.
Also in either ending what you choose to say will bring about different variations but theres just the 2 core endings.
Well not only are there different endings but different events by making a different choice in about every part of the game.
-You can fight Saren a second time or make him commit suicide
-You can kill Wrex or keep him
-You can pick Ashley or Kaiden to die on Virmire, in different locations too
-You can save the council or not
-You can pick Udina to be in the council or Anderson
-You can have sex with Ashley or the alien chick
-You can kill the woman on Virmire you find in the lab or let her live
-You can kill the alien on Feros or let her live
-You can kill the rachni queen or let her go