Posted 18 May 2006 - 10:00 AM
Since you are still discussing hardware, my recommendation would be to replace the hub with a router for a couple of reasons. First, with your setup, if the one computer that has the Internet connection is shut off, none of the others are accessible... not ideal for a web sites.
A router will assign addresses to the internal computers automatically, so all you need to do is foreward port 80 to whichever computer you plan on using for a server (sounds more complicated than it really is). The additional benefit of a router is that almost all of them have built in firewalls. Plus you don't have to leave the host system (the one with the Internet connection) on all of the time. So your connection will go modem->Router->all 4 computers. Routers are relatively inexpensive.
Your ISP may have port 80 blocked, which means you will not be able to host, or in some cases, for an additional fee, they will upgrade your account to a business class and open it. You will have to check on that yourself.
Basically any OS can be used. The server software depends on what kind of pages that you are wanting to host. Apache will probably be all you need (if you are doing static html), and it is free. Otherwise there is Tomcat for .jsp, and a dearth of others. I am running a Tomcat server on an XP home system... works just fine. Not the ideal solution for heavy duty use, but for my purposes, it works just fine.