Tomcat 5.x and Tag Libraries

[nrapagnani]

I've had some trouble getting Tomcat 4.x to work with JSTL.  On a separate
machine I've installed Tomcat 5.x and have successfully used JSTL.  The
problem know is that I don't remember what I did.  Does JSTL come standard
with Tomcat 5.x?  Is that why it worked for me?  If not, which JSTL should I
try with Tomcat 5.x?
 
Sorry for the dumb questions.  
 
Thank you in advance.