Day 10-Unsupervised Tools

There is already a tool for unsupervised classification in ArcGIS 10, Iso Cluster Unsupervised Classification (Spatial Analyst). I think to get a handle of what exactly it does I will download data that I can verify (ie the pacific northwest) to see how it works before extrapolating that to an area that I have never been. Easiest place to do that? Gasworks!