Upgrade to Tomcat 6 on Ubuntu

[Mukerjee, Neiloy (Neil)]

I am running Ubuntu 8.04 and already have Tomcat 5.5 installed, but I am told 
that in order to properly use another program (Solr 1.3), it would be best for 
me to upgrade to Tomcat 6. However, I have tried going through the regular 
install process of Tomcat 6, and it doesn't seem to overwrite Tomcat 5.5 - am I 
misunderstanding something or leaving a step out?