Simple Heatmap Generator

The simple heatmap generator is available as a template in the google docs template gallery. It's basically aimed at being a quick way to see what your data will look like as a heatmap. For the final product I would suggest you use a great tool like R.

Google spreadsheets do have advantages though, like allowing you to embed spreadsheets in webpages.

Give it a try and leave your feedback in the comments.