The Netbeans integration was for a long time developed at http://mevenide.codehaus.org, it was moved to netbeans.org and will be part of standard NetBeans distribution since 7.0. It allows to load any Maven 2 project into Netbeans and start coding immediately. To get a current feature list along with screenshots, description and hints please refer to the NetBeans.org wiki page.
The Maven integration is easily accessible in NetBeans 6.0, 6.1 and 6.5 via the Tools/Plugins dialog. In 7.0 and later it's part of the standard installation. More detailed instructions on installation available (for older versions of NetBeans) at the Mevenide site.
Bug, enhancements and feature requests are to be filed in the NetBeans.org issue tracking system.