Microsoft has divided share point products in two parts. One is called as WSS (Windows SharePoint services) and the other is MOSS (Microsoft Office SharePoint server). WSS is the platform on which MOSS is built. The WSS part is licensed through Windows 2003 server and it does not cost. MOSS is separate product by itself and it needs licensing and it has a good amount of cost J . WSS is good for small team and small projects. MOSS has extra functionalities in other words value added services. So the choice between WSS and MOSS will depend on budget of the project and the VAS provided by MOSS.