He said he's using a e-net switch, so it's logical to assume he's got more than one computer/device connected to the modem. In that case, port-forwarding is going to be an issue.
Easy way around it is to replace the switch with a good quality router. Dlink is a good choice (DI-704), plus they're extremely easy to setup forwarding on. They also have the dynamic DNS feature built into most, which will contact your DNS host and keep you IP updated (assuming you have a dynamic IP).
Once you have that going, just turn on Apache and serve away. If you just want people to have access to files, and don't want the hassle of programming a page to list them, then create a subdirectory and enable the index view of that subdirectory via htaccess.
Other option would be to setup an FTP server.