Also try looking at the DTD for the examples with
Tomcat, sometimes seeing an actual web.xml with real values. Currently I am reading the Exam Cram book on the SCWCD exam, and they kind of describe the tags, but I feel they are a little inadequate for someone just learning. I mean I have already passed the SCWCD a while ago, and I was even a little confused.
I think the Servlet/JSP specs have a little more description too.
Good Luck.
Mark