Recources for group work

Group work is difficult online. I know some teachers believe that the formation of groups is easier online because often online students do not "want to be with their friends" but I look for the early posters and the late posters. I want the early posters to be together because the frustration is high when some in the group want to get started and others are "last minute" people.

Here is an interesting resource on tools for groups.
http://www.ratedcolleges.com/blog/2009/50-fabulous-web-tools-for-group-projects/