I was poking around looking for a specific course offered by the Department of Homeland Security. You can see their training list at Commercial Facilities Sector Training and Resources
Instead of finding what I was looking for I came across a PowerPoint briefing from one our nation's Protective Security Advisors (PSA). Check it out at Securing the Nation Nation’s critical infrastructures one community at a time
It is about four years old, but it does a nice job of showing how everything fits together at the Federal level down to the role of the Protective Security Advisor. Every state has one designated. If you don't know yours be sure and make an appointment to meet with him or her.
Dave Holcomb is Washington State's.