Field Level Security with CRM 2011
This is a new feature which has been given with CRM 2011.
With earlier versions we had to write java scripts for hiding of fields. This required checking the user has privileges and going on about it
With CRM 2011 we can do this using the field level security. We no longer have to write any java scripts for this.
However there is one thing. We can only use field level security with custom fields that we have created. Not with the system fields.
This contains a very good article on this.http://msdn.microsoft.com/en-us/library/gg309608.aspx