Nt workstation /Sharing

Since we have begun using nt workstations, and some shares have been enabled on the workstation. The communications group inform us that they notice broadcasting on port 640?, that these systems are displaying them selves as server

I believe thismay be associated with having shares enabled. Unlike 95, nt automatically I believe has file and print sharing enabled.

Does anyone know if there is a way to prevent users from creating shares on a nt workstation?.

Any help appreciated.