Hi,
You can try the following Terminal command to see what's listening on port 8080:
sudo lsof -i -nP | grep "8080 (LISTEN)"
The first part of the result is the name of the process (program) that is listening on port 8080.
If the name is 'httpd':
This probably refers to Apache, the built-in web server. Check to see if web service is enabled in Server.app. If you believe the built-in web service should be disabled, but appears to be running anyway, you can try:
sudo apachectl stop
which should stop any httpd processes. Reboot to make sure it sticks. If it doesn't stick, that means some other web-based service thinks it should be running. In Lion Server, there are various services that want Apache to be enabled, including Web, Wiki, Profile Manager, iCal Server (for /webcal), and Mail (if webmail is enabled). Try running the following command and report back with the results:
sudo webappctl status -
anything other than 'empty array' means the server believes some web services are configured to be enabled.
If the name is NOT 'httpd':
This probably refers to some software you have installed. How you deal with this depends on the nature of the software in question. You can try using Activity Monitor to terminate the process (be sure to set it to view All Processes), but the process may be automatically restarted if it was configured that way. If so, you'll have to undo that configuration, perhaps by removing the associated LaunchDaemon from /Library/LaunchDaemons and rebooting.
HTH,
-dre