Recently, I read a great post from Shawni on 71 Toes on how her parents dealt with fighting between her and eight siblings growing up. It is such a great tool, I just had to implement it with our kids when they started fighting and I'm here to say it works!
She calls it the "fighting bench," but we use the step in our garage instead. (These two look thrilled, don't they??)
The kids aren't allowed to say all the bad things their "bench partner" did. They have to take responsibility for what each one has done to start the fight. Even if they're really stubborn (like one little girl seems to be). I make them sit there until they decide to fess up.
They have to apologize.
(There's usually funny faces involved.)
As they bond and become great friends again.
So, now when I hear bickering and whining, I just say: "Head to the step!" The kids may not be happy, but they know exactly what to do.
Intentional parenting, that's what it's all about. (A quieter, calmer house isn't so bad either.)