I'm excited to announce our March 2011 IIS Community Newsletter is published
Here is the link to the March 2011 edition -
If you run Sharepoint 2010 in one forest, users in another forest and a 1-way forest in-place. There is some additional configuration needed in Sharepoint 2010. I included links below that discuss the details. My post is not to be in-depth how to setup, rather share a tidbit not discussed in documentation (not that I could find). Thanks to a smart co-worker and process monitor, it was found there is a registry entry, the application pool needs READ access. You can either manually grant permissions on the server or add registry permission in AD Group Policy. Hope this helps.