I created this a while back to add large numbers of users to a group when I got tired of manually adding 150 users for a new application deployment. This will allow you to select a text file and import all of the users from the file into a group (without using Ldif or another tool). It will search the tree for your group (and confirm the group) then it will confirm the user list before adding them to the group.
I will include the Winbatch source for anyone who would like to check what this is doing behind the scenes. I cannot guarantee this won't bork up your network.