The Hills (Heidi & Lauren) Argument?!?

I don't like the TV show The Hills on MTV, but I did watch the first disc of Laguna Beach. I thought it was ok. Anyways, there are a bunch of articles saying Lauren & Heidi got into a huge fight and I'm just curious what it was about. I can't find out what happened exactly. I watched one episode of The Hills once and they were good friends. So I'm just curious what the fight was over and how it happened. So can someone tell me all about it? Was it over a guy like it was in the show Laguna Beach with Kristin & Lauren?