The messages on Blender forums and boards are countless about smoothing problems. Most of the time, the users report black blotches on the surface of their models, while using the Set Smooth on them. This article is not a tutorial. It's more a discussion, a collection of observations and know-how. It is intended for beginners, but seasoned users could also find it valuable in their own attempts (as ressource or reference) to help beginners. Isn't the community about helping each other, after all?
For Blender: 2.44 - Japanese version available()