AxCMS.net is a free CMS offering that you can download and run on ASP.NET 2.0 today. Here are a few AxCMS customers deployed on it today: http://www.porsche-design.com http://www.weimar.de http://www.codezone.org.uk http://www.staedtler.com http://www.vorota.de http://www.akb.ch http://www.JobScout24.de http://www.flyerwire.com http://www.plana.de
Here is a blog you can read to follow it. You can learn more about it and download it for free here.
Hope this helps,
Update: Anders pointed me at http://www.umbraco.org/ as well -- which is another free .NET CMS system to check out as well.