The 14 October 2009 issue of Rootsweb online newsletter, Rootsweb Review, has a very informative article about copyright rules. It explains what is and isn't covered under copyright, how long copyrights last, etc.
It is worth checking out given the need we genealogists have to record and make reference to the research of others.
In time you can read the October issue of the Review on line at the RootsWeb Review Archives. But if you want the latest copy delivered to your mailbox, you can sign up. To subscribe or to read the archives go to http://newsletters.rootsweb.ancestry.com/