Are there clans in Halo 3?

I was wondering if any one could tell me how to make a clan.

How can I upload a cs map I made to GameSpot?

I like making custom maps and I think it'd be cool to share a couple with the gamespot commuity.

Is Coagulation still on Halo 3?

It came up in a disscussion and I don't have it yet so could some1 plz tell me?