Very good article to describe the tools and techniques to view and modify AD ACL (permissions):

http://social.technet.microsoft.com/wiki/contents/articles/6477.how-to-view-or-delete-active-directory-delegated-permissions.aspx

Two free tools:

https://adaclscan.codeplex.com/

http://www.ldapexplorer.com/en/freetools.htm