If you've ever heard the criticism of Intelligent Design that it's not a scientific theory and should therefore not be taught in public schools you might be interested in perusing the information at Evolution News and Views.
Casey Luskin amasses a formidable array of resources which collectively make the case that ID is every bit as much a scientific theory as is anything else.
Along the way Luskin mentions the demarcation problem which, to my mind, makes the whole question of the status of ID moot. The demarcation problem is the challenge of trying to determine what it is about science that separates it from non-science. Most philosophers of science agree that there really is no clear boundary or demarcation and that the best way to define science is to say that it's simply whatever it is that scientists do.
If that's the case then it seems a bit futile to insist that ID is not science.