If you can, try not to in front of the children. Children do take in a lot and remember even more. Depending on how old the child is talk to them and tell them that sometime mommy and daddy argue. But, make sure they realize that does not mean you love each other less. That little bit of reassurance does help.
My friend and his wife what they do so as not to argue in front of their 3yrs twins. They text each other or one will be on PC, IM'ing the other will be on cell/black berry or laptop out in the garage, back yard. So the kid won't hear. I know I laughed too, but the kids don't hear the fighting.