That's not really the architecture of the system. So what is the end goal here Avoiding paying for MOSS but serving content
The architecture would be that would would create your web parts and deploy them to each front end web server, if each front end web server shares a content database, you can display information from any site on any server.
If the goal is to serve content inside the web parts and manage it in a central place (ie, place the same content on every page and edit it in one place) then you would look at "Shared Content" i believe in MOSS.. if WSS is all you have then you would need to do a small bit of custom programming to accomplish this but not much.
Hope that helped