This article was first written in November 2007 for the BeezNest
technical website (http://glasnost.beeznest.org/articles/365).
The easy part is to right-click the directory in GNOME and select "Shared directory…", enter the sudo password, then select "SMB (Windows client)"  and possibly unselect the "Read only" checkbox.
This will enable the SAMBA sharing of the directory.
Now when connecting from Windows, you will be asked to enter a login and a password, but even if you use correct a login/password pair, you won't be authorized, because you need to enable the access fr