Modem sharing

I have a 5 node network. A server running win 2000 server and 4 PCs running XP Home. I have a modem connected to the server and PC1 each with a setup to AOL. I need to give internet access to PC3 and PC4. I’ve tried following the Help in Windows, but still can’t get access to the internet. I am assuming that either PC1 or the server has to maintain a connection to AOL and then the others can use Internet Explorer to move about the net. Any help would be greatly appreciated. Thanks