Here is a web site that has been a part of the Dean campaign in organizing leaders of the grassroots movement. It is going onward with the continuation of Dean's mission to empower Americans to be able to make changes in campaign financing and media control among other goals.
This was National Grassroots for Dean, and will continue as National Grassroots. Probably will be able to find Meetups for this in many places.

http://www.NationalGrassroots.us/