What is the conflict between Old Major and Napoleon in Animal Farm?I dont understand how their conflict relates to the Russian Revolution.

The major conflict usually discussed in Animal
Farm is between Snowball and Napoleon, so this is an interesting question.
 Just so we are both on the same page, remember that "conflict" describes characters in
the story who either have incompatible goals or some underlying psychological
division...not always a physical conflict.

Napoleon and Old
Major don't have a direct, active conflict in the way that we most think of.  Old Major
was the initiator of the revolution in that he was the one who initially put the idea
into the other animals' heads.  He was a catalyst, but notice that he didn't act until
he was very old, used up, and had nothing to lose.  Old Major doesn't even take part in
the actual "revolution" on the farm.

In the terms of the
Russian Revolution, Old Major could be seen as sort of a Karl Marx.  He's an Idea Pig.
 He dies before the revolution but he sort of gets the ball
rolling.

Napoleon is more like a Joseph Stalin.  He takes
the ideas of the revolution, as given by Old Major, and exploits them.  Napoleon is not
afraid to get his hands dirty.

The conflict between them
would be seen as more subtle; Napoleon is in almost constant conflict with the ideals
that Old Major talked about.  The farm animals have come to believe in those ideals and
they measure events on the farm by them (in their own, limited way.)  So the conflict
between Old Major and Napoleon is one of ideas.

The Russian
Revolution is the same way.  People didn't get involved just to set Stalin up as the
dictator of the Soviet Union.  He had to twist the energy of the revolution to his own
ends, and had to constantly combat the effects of being measured against Marx's original
ideas.