You may know the Unit Tests Code Coverage Plugin for NetBeans. It provides a good way to see testing coverage results within the NetBeans IDE. It works with EMMA and is initially developed for NetBeans 6.0/5.0.
Unfortunately, this plugin is not compatible with NetBeans 7.0.x. In addition, it is hard to find a link to download the NetBeans 6.x version of this plugin (the link you can find in the plugin page leads to a tutorial). To finish, its maintenance seems to be stopped.
So, I've decided to package a NetBeans 7.0.x compatible version, and provide a NetBeans 6.9 version too :)
You can find this new version at plugins.netbeans.org(...)for-netbeans-7-0. There is a ZIP file that contains NBM files for NetBeans 6.9.x and 7.0.x.
Hope you'll find it useful.