I downloaded and installed ICEFaces 1.7.2 and its modules for NetBeans 6.1. My conclusion is that is not ready for primetime on NetBeans.
I would recommend that you read the release notes very carefully. The newest version of ICEFaces is not JSF 1.2 compliant. It needs to run in compatibility mode. This requires you to modify the faces-config.xml and web.xml files. This is a major pain point.
The next thing I noticed is that the design-time implementations are not complete. The ability to visually manipulate the components needs some serious work.
I attempted to do one of the tutorials to create a CRUD application using Netbeans. It was very flaky and did not cover the details adequately. In the end I got the application to deploy, and I could click on the table rows, but it did not work as it did in the tutorial.
I have used ICEFaces in the past and I do like their product in general, but it needs to come up to speed with the rest of the world on JSF 1.2 .Its support for NetBeans needs to have more than token capabilities, and it should account for its compatibility issues without intervention from the end user.