Eclipse in its most banal, downloaded form, is simply an awesome
Java editor, capable of allowing you to create, compile and debug Java code written against the JDK.
Unfortunately, the JDK only included the basic Java packages, like java.util, java.lang, java.awt and java.swing. To develop Servlets and JSPs and EJBs, you need some form of
J2EE tooling, or at least for you, a Servlet/JSP tooling.
IBM's Rational Application Developer is Eclipse with all sorts of J2EE tooling added in for you. Of course, it comes with a price tag.
Browse around eclipse.org, and you'll be able to find some 'plugins' that should allow you to do JSP and Servlet development. I've seen
http://www.myeclipseide.com/ provide a bunch of plugins for eclipse at a pretty cheap price - cheaper than IRAD.
But, out of the gates, Eclipse won't allow you to do JSP and Servlet development. Sorry.
-Cameron