You can get different transition effects from one colour to another.
Right-click on the data area of the graph, then click on Format Data
Series. The Patterns tab controls the colours in the bars of the
chart. From here you can click on Fill Effects in the Area panel, and
just play about with different selections (and there are different
tabs as well), until you achieve an effect you like.

Hope this helps.

Pete

Mike,

By "progressive coloring," I think you mean a gradient.  But it won't respond to the value
of the data point.  That sounds more like conditional formatting in a cell, and isn't
available on charts.  You could do it manually, or via a macro.

For a gradient, right click one of the columns or bars (don't click it a second time, unless
you want to apply the gradient to only that column or bar), and choose "Format data series,"
then select the Patterns tab, then click "Fill effects," then select the Gradient tab.  You
can apply this to a column, bar chart, area chart, and others, but you can't apply a
gradient to a line chart.

In the future, you might have better results in microsoft.public.excel.charting.