Include a few stories. It would be best to have one or two of these stories from a well-known author. This will show a publisher the potential of the anthology idea. If you can't get commitments from "name" authors, at least get blurbs from them.
Write a proposal. Detail the anthology idea, the authors who have committed and those you will be pursuing. Mention how many stories the book will contain and how you will market the anthology.
Submit the proposal and a couple of stories to publishers who accept anthologies. Start with bigger publishing houses and work down to the smaller presses. If you have sold other anthologies, mention this in a cover letter.
Consider finding an agent. Agents can get the proposal to publishers you might not be able to reach yourself. Some publishers do not accept unagented manuscripts.
Network. Attend writers conventions and conferences, approach authors and agents and mention it on writer's blogs and in chat rooms.