Instead of using the JSDK2.1 by itself, I would recommend getting the J2EE1.3.1 instead. J2EE includes everything in the Servlet API and is more current (Servlet Spec 2.3).
Next I would get Tomcat (4.1.12 I believe is current) from http://jakarta.apache.org.
This is a free webserver that implements the 2.3 spec.
Finally, I would become familiar with the directory structure of the Web ARchive (.war file). ANY J2EE server (Tomcat, WebLogic, WebSphere, JBoss) MUST support this. The .war file and it's structure define exactly what you are looking for and more. The location of static file, config files, servlet classes and anything else required are predermined. This not only standardizes practices, it ensures that your app is portable since the structure is supported by each server. You will not get that portability coding to the 2.1 spec implementation.
[ October 04, 2002: Message edited by: Ken Robinson ]