Mommy Monday - Rivalry

My ten year old and my seven year old are having a lot of problems with sibling rivalry and constant bickering.  I've tried all the things I know to help this but so far it's just getting crazier.  I know my sister and I drove my mother nuts so maybe it's just punishment for my crimes.  It's one of those things that seems to be a problem for even the best of moms.  The two girls share a room right now and I am considering rearranging the house so that they are in different bedrooms but this is a lot of work and I am not ready for the younger children to be down in the basement bedrooms.