Tutorial for User Management and Authorization Roles in CRM is needed

Hi SAP Security Gurus.

Please help me understand if Concept and Authorization process in CRM 7.0 and CRM on Demand is the same. I mean uers, role creation etc. I have done ADM940 and know auhorization concepts in gen. I would highly appreciate if some knowledgeable guru can help me understand Authorization concept in CRM 7.0 and provide Links or tutorials on the same as well.

Cheers and thanks in advance.

Priya