If you system creates a 'default' route entry in your routing table you will need to remove the route before running PPP. You can check this by typing route. To remove the default route type route del default at your prompt. Here's an example:
info:~# route Destination Gateway Genmask Flags MSS Window Use Iface localnet * 255.255.255.0 U 1500 0 24297 eth0 loopback * 255.0.0.0 U 3584 0 18 lo default * * UG 1500 0 117874 eth0 info:~# route del defaultOnce you have 'pppd' and 'chat' installed in your /usr/sbin directory, you may use this PPP Script to connect. You will need to edit the script for your modem port, your modem speed, your username and your password.
Once this is configured you will want to check out the Linux Parameters to configure your DNS settings.