I want to create more than 100 public group in Enterprise Edition. is ther any governor limits for a public group.
Little googling let me find this post that says that there's no limit to public groups, but a limit to 300 sharing rules(and no more than 50 based on criteria based rules) which mentioned here and that's could be the problem.
Edited: As mentioned by Simon Govaert the links in the first post are dead. But I did create 5000 groups in my dev org - encountered no problem at all, which partially asserts the statement below that you at least could create 5000 groups.