These calculations are taken from The Logical Trader by Marc Fisher. He feels that Moving Averages are misleading in that they are based solely on the close of the day (or incremental time period). He feels its more accurate to judge the market trend by using prices that went off in the meat of the market. To do that he calculates a Daily Pivot Price.
Daily Pivot Price = (High+Low+Close)/3
For the purposes of creating a Moving Average using this, simply plot each day's pivot point on a chart and calculate the slope.
I like to derive both the 30-day and 5-day slopes to calculate the short-term spread between the two, which I feel, gives me a more accurate picture of short-term market sentiment.
The attached document is th 30-day Daily Pivot Price Moving Average for the S&P. The Slope for the entire period is presented (which obviously points to an upward trend). The slope for the last 5 days of trading is also presented (which shows a downward trend).
The spread between the longer-term (30-day) and shorter-term (5-day) slope is negative, indicating a bearish bias.
That's just my 2 cents. The problem with this, like any indicator, is it's based on past, not future data (oh, wouldn't that be nice). But, needless to say, I'll be shorting almost everything tomorrow.