System.Diagnostics.Process class provides APIs to get lots of information about Process, but it doesn’t expose a few capabilities. For example, you can’t get information about the session id or the owner of a process. We will be exploring additional functionality after the Whidbey release.
In the meantime, http://msdn.microsoft.com/msdnmag/issues/02/06/debug/default.aspx is a good article about how to get process information in unmanaged code. It shouldn’t be too hard to convert the C++ code to C#.