Can someone please give me a detailed run down of pivot point analysis (the method where you end up with a pivot point, R1, R2, S1, S2 etc.).

I'm a bit confused with these specific issues:

1. What exactly is a pivot point? (sorry!)

2. Why TWO support and resistance points?

3. What is the best timeframe for using these calcs (hourly? daily? weekly? etc.)?

4. Are these calcs just a more complicated way of deriving trend lines?

5. Does anyone actually find them an effective forecasting tool?

I found this pivot point calculator if anyone is interested: http://www.futurestrade.com/

I'd welcome any general comments on the subject.

Thanks.

James