If you are using Netbeans 7.0 beta, the plugin list may not show Selenium Module for PHP. To install it, navigate to Tools>Plugins>Settings and click on Add. Then, in the name field, enter something like “Netbeans 6.9 beta” and in the URL field, enter the following URL:
http://updates.netbeans.org/netbeans/updates/6.9/uc/final/beta/catalog.xml.gz
Now, reload the cataloge and you should be able to install Selenium Module for PHP.
Happy developing.