FCIV.EXE is a handy little utility to snap a MD5 hash of a single file or multiple files. Optionally it can recurse directories and produce XML output. http://support.microsoft.com/kb/841290
MD5SUM.EXE is a more commonly used utility that runs on a number of different platforms. A good Wikipedia article with links can be found here and a Win32 binary can be found here.
