How to change the location of TOMCAT_HOME/webapps on Tomcat 4.1.x?

Alessandro A. Garbagnati

That is explained in the Server Configuration Reference - The Host Container official documentation page.
Just change the appBase attribute of the <Host/> tag, according to this:

The Application Base directory for this virtual host. This is the pathname of a directory that may contain web applications to be deployed on this virtual host. You may specify an absolute pathname for this directory, or a pathname that is relative to the $CATALINA_HOME directory. See Automatic Application Deployment for more information on automatic recognition and deployment of web applications to be deployed automatically.
The same works also on Tomcat 4.0.x.