tattling had become such a "regular" thing for a while because ALL my kids were getting older 3's and 4's, (they KNOW the rules and try to enforce them all day long) or (would get upset with someone and just tattle to get them in trouble) SO.....I started a New Rule. "Tattling is Time-Out!" When someone would come to me to tattle (waste of time tattle) "he hit me" or "she won't share" I would respond with..."what's the rule?" they would say "tattle is time out!" I would ask the "tattler" if they wanted to go to time-out? of course they would say "no". So I would tell them to "work it out". Talk it over, tell your friend you dont like that kind of play, or that was too hard, or please share with me and I will share with you.
Encourage kids to work out their own "troubles" rather than run to an adult everytime something doesn't go their way. Builds communication skills, and get them OFF YOUR BACK!

I do ocassionally say "is he hurt or bleeding?" they will laugh, then I say "go work it out!"