Heat Map template

Hi,

I need to devlop a heat map along the following lines.

The data elements will be displayed on a 5x5 square grid. Each axis of the
grid has a 1-5 scale.

The data need to show how their value (X axis against Y axis) has changed
(or not, it is possible that they will stay the same) over time - 2 or, if
possible 3 months, preferably as an arrow (I can probably do this bit by
using one of the Webdings type fonts).

There are an unknown number of data elements, but in reality the range is
likely to be between 6 and 35.

I would like the map to be updated as the result of selecting a button
rather than in "real-time". I can code this bit, but don't know where to
start on building the chart in VB - can anyone point me to a tempate or model
that I can use as the basis of what I need?

This will be done in Xl '07 under Vista Enterprise

TIA

Dave