Class Meetings

Ok, so I know I want to have weekly student run class meetings in my future classroom, but what is the best way to structure them.  When I was volunteering in a 6th grade classroom a couple of years ago I was introduced to weekly student run meetings.  I thought it was such a great idea.  The students were able to address issues that were important to them and involved every member of the classroom community.  The teacher pretty much stayed out of it, accept in rare circumstances where he felt he needed to intervene or interject. 
I have not been in a classroom where they have regular class meetings since I was in the one I previously described.  I was wondering if anyone else out there is seeing regular class meetings in their placements.  Some important key parts of the meetings I saw were that students ran the meetings and came up with the topics and issues discussed; there were clear guidelines and agreed upon rules that students followed such as being respectful of one another and only the person with the ball could talk.  Does anyone else have any ideas or knowledge of resources to help structure student run class meetings?  What are some other key parts?