Module WhosOnline from the Joomla core displays the username, if so selected in the module parameters. My modified module code allows to choose between username and (real) name in the module parameters, and displays accordingly.

• Base module copyright owner: Joomla!
• Base module version: 1.5.x
• Tested with: Joomla 1.5.8 - 1.5.10
• Files changed: mod_whosonline.php, whosonline.xml, helper.php, default.php
• Change marks: find bco in the file
• Download: bco_whosonline.zip
• Install: replace all files changed or re-install the module with the downloaded zip file