VFR/IFR Flight Plan:
1. Call 1-800-WX-BRIEF
2. Get current and forcasted weather.
3. File VFR flight plan if you wish to do so.
4. Call the number above to activate your flight plan before departure, or contact FSS over correct Freq. Located on the VFR Sectional as RCO. Usually 122.2
5. Close the flight plan either by phone after you land by calling the number above, or over the radio with FSS before you land. Most of the time you will not get them on the radio once your on the ground.

VFR Flight Following:
1. Request this with departure control after departure from a non-controlled airport, or from approach control if you are wanting traffic advisories when entering busy airspace. You can also request this before you taxi from clearance delivery if the airport is big enough. Sometimes this is combined with ground/tower during slower traffic times.
2. ATC/clearence delivery will give you a squawk that will be good for the remainder of the trip. "most of the time"
3. You can cancel Flight Following at any time unless you are instructed to stay on with them due to high traffic. Class B usually.
4. Before you arrive at your destination, the controller will tell you that "radar services are terminated, squawk 1200". This usually occurs when the control tower is not in operation, or doesn't have one.

Hope this helps.