OS-X FAQ has a pointer to a great article on how to get Tomcat (the reference implementation for the 1.2 JSP/Servlet spec) running under "Mac OS X".

As we are doing a lot of servlet development rightnow, this is great news. The article comes with two version s of the instructions – the 15 step GUI (newbie) version, and the 4 step command-line version (wget, gnutar, cd, startup.sh). I love having a "real" command line again.