To Configure Confluence to run on port 80 alongside another web service already on Port 80, you can add an "address" attribute to the connector element where address="<IP address on which Tomcat-Standalone is running >"

Change the server.xml file by adding the element:

<Connector className="org.apache.coyote.tomcat4.CoyoteConnector"
address="192.168.1.1"
port="8080" minProcessors="5" maxProcessors="75"
enableLookups="true" redirectPort="8443"
acceptCount="100" debug="0" connectionTimeout="20000"
useURIValidationHack="false" disableUploadTimeout="true" />

Also change the hostname from localhost to the relevant host name, in the file above, on the same IP.