If you develop small utilities for Team Foundation Server a lot you might want to save some time and use a project template (see bottom for file attachment) that already comes equipped with the correct references to the Team Foundation Object Model (Microsoft.TeamFoundation.*.dlls) as well as the most important using statements and a few lines of code to get started.

Download and installation steps can be found here http://msmvps.com/blogs/vstsblog/archive/2009/01/14/download-visual-studio-2008-project-template-for-tfs-utilities.aspx