Listiki.com has just been launched. Listiki is a real-time collaborative list building tool that allows you to create, share and edit lists of anything.
To give you an idea of what this is about, you can watch this short screencast - http://goo.gl/MGWk that will give you an overview of Listiki's core features. Listiki plans to release many updates over the next few weeks including a pretty nifty API, embedding & media attachements.