If you want to work with serial communications at a low level on Windows NT, there is some information in MSDN Library under Platform SDK/Windows Base Services/Files and IO/Communications.
makes the libraries underpinning the
package; evaluation libraries are available for download, as are
numerous example programs in various languages.
McMillan has written a sockets how-to guide that can be found at
www.python.org. Much of the
information in this section was based on his guide.