If you've ever wanted to look at managed localizable resources, grab a copy of ResView from the BCL team demos page, or at this site http://www.gotdotnet.com/team/clr/bcl/demos/demos/zipfiles/ResViewCS.zip. ResView will allow you to look at the resources in a main assembly, a satellite assembly, a .resources file, or a ResX file. This is useful for tracking down localization problems. It will also look for some very simple but common naming and build errors. If you're getting a MissingManifestResourceException, this is a good tool. Internally, we only use ResView and ildasm to track down the vast majority of our localization issues.
Note: I updated ResView on 1/13/2004 to detect more problems in user assemblies.