Mike Cohn has a great introduction to the concept of story points and how to think about them on his blog at MountainGoatSoftware.com.
It is a brief introduction that gives a definition of story points, what factors go into determining story points, and how they should be used in relative estimation of effort.
The article provides a simple, relate-able example to help you understand how story points would be implemented in the real world.
If you are new to the concept of story points or are contemplating using them in your development process Mr. Cohn's article is a good place to start.
Question: Are you using story points in your development? Please leave your answers in the comments below, I want to see your perspective.