1) Install an Ethernet card in each computer and a second one in the server to connect to your DSL modem.
2) If using Win 95, 98, or ME as the server assign an internal IP to each each Ethernet card (For the card connecting to the modem use an address of 10.0.0.xxx and for the card in each PC use 192.168.xxx.xxx) use these instructions.
3) Make sure you use a cross over Ethernet cable between the two PCs and a straight through Ethernet cable to the modem.
4) If you are using XP or Windows 2000 as the server, do not set an internal IP address on the two Ethernet card that connect each computer, make sure they are assigned to use DHCP.
5) Choose your PPPoE software and look at the instructions for using ICS here.

1) Install an Ethernet card in each computer.
2) If using Win 95, 98, or ME as the server assign an internal IP to each each Ethernet card use these instructions.
3) Use straight through Ethernet cables for all connections if plugging your modem in to the uplink port on your hub. If you do not have an uplink port please use a cross over Ethernet cable.
4) Choose your PPPoE software and install it on both computers and you can connect with both machines via the PPPoE software.

Note: For the above method use straight through Ethernet cables for all connections.
If using the above method, please choose the router you are using for instructions here