Want to know what all the layer blend modes in PSP do? Look
The blend mode layer is set on 80% opacity in all these examples. When making icons, always play with the opacity of a layer to see what looks the best.
(Sorry this one is smaller - Photobucket resized it.)
The three most common blend modes are exclusion, soft light, and multiply. Experiment with using different colors than just the standards which make the same boring icons that everyone has seen already. Again, remember to play with the opacity.
The blend mode layer opacity is on 100% in these examples.
Check out my earlier
Guide to Making Good Bases, if you want.