I want to start Tomcat 6.0.29 on port 80. My OS is CentOS release 5.5 (Final) I changed following line in $TOMCAT_HOME/conf/server.xml
You can change AUTHBIND property of "/etc/default/tomcat6" to "yes" as follows
AUTHBIND=yes
Restart your tomcat and that will enable you to use available privileged port (1-1023).