MacFile in Windows 2003
.. or how to share folders from Windows 2003 with Macs via AFP/MacFile/File Services for Machintosh
I don't know what I missed, but this is the one type of sharing that requires using Computer Management.
Right-Click My Computer, Click Manage. Click on Shared Folders. From there you can right-click white space and use New Share to create new shares. The third screen in the dialog allows you to pick Windows, Mac or both.