Here's a great excerpt from "Remote Sensing: Principles and Interpretation" by Floyd Sabins -- an amazing textbook (written by a Chevron remote sensing expert, interestingly) which has informed a lot of the research I've been doing in multispectral sensing. Check out the book here:

http://books.google.com/books?id=Rt3NQwAACAAJ&dq=remote%20sensing%20principles%20and%20interpretation&source=gbs_book_other_versions

This section, interestingly, covers the use of UV and near infrared imaging to identify and characterize oil sheen on water -- I'm eager to try our UV camera to detect sheens. Above, you can see where oil sheen reflects significantly more than open water in both the near UV and near IR ranges -- making our modified cameras a good candidate to pick out sheen more reliably than regular visible-light photography. I'm going to test this with some motor oil soon.