Drag-and-drop to trash all the folders NetBeans 6.x.app, glassfish-v2.x (if installed) , glassfish-v3 (if installed), sges-v3 (if installed), apache-tomcat-x (if installed)
Delete ~/.netbeans/6.x if you don`t want to save your NetBeans settings or if your IDE behaves strangely.
To clear the history of the installed software on Mac OS 10.6 Snow Leopard delete /private/var/db/receipts/org.netbeans.*, glassfish-v3* (if installed), [...]