By default JBoss 4 ships with 3 preconfigured connectors:
HTTP on port 8080
JK on port 8009
HTTPS/SSL on port 8443 (may be commented out by default)
The connectors are configured in the server.xml file. Here you can modify which port they listen on and resolve possible port conflicts (or use the binding service for that).
If you want to enable compression for the HTTP protocol you can add the attribute compression="on" to the HTTP connector tag. With compression="force" you may force the browser to accept compressed contents. For more details see the Tomcat documentation. One side effect of enabling compression is that browsers may not render the page until the whole page has been transfered to them, the last servlet filter is through and the stream is closed. This may be useful if concurrent requests with the same HTTP session confuse your webapp for example because you do some heavy post processing in a servlet filter.