I have a asp.net mvc project and persistent is handled by repositories . Form authentication is used. Now I need implement authorization . For example , I need to ensure a manager user can only open his/her taskes and assign workers to the taskes. A worker will only see taskes that have been assigned to him/her. A super-moderator can edit everything. 
Is there any ready to use framework that allow me to define permissions ? 

I am in the process of evaluating Ayende Rhino Security . Where can I get more examples codes ? What is your opinion on Rhino Security ?  

My project use Linq to SQL and has not made use of NHibernate. Can Rhino Security works without NHibernate ?