Determining the copyright status of a published work depends on a lot of factors, even when the author died! This is a very interesting Flash-based tool that helps you determine whether a printed work is protected by copyright or not. There is also a physical version of the copyright slider that you can order if you are so inclined.
“Fair Use” for legally using media is not black and white. To help sort out the fair use criteria, the University of Minnesota has created an online (or PDF) worksheet to help you determine the extent to which what you would like to do is protected by fair use.