Airport Base Ports


When using a graphite model airport base station(802.11b model) that does NOT have dual ethernet, is it possible to share the 56k connection to a computer plugged into the ethernet port, and to users connected to the wifi network?
Not to the computer on the ethernet port, I'm afraid, since the ethernet port is not configured to allow it. However, you could use the computer that has ethernet to do the dialling into the network (that is, use the modem on that computer, and share the connection from that computer via ethernet to the airport station) and then any computers using that airport station will be able to share that Internet connection.
That defeats the point of having an airport for me, since the purpose is to provide a wifi 56k without leaving a computer on.