SLIP/PPP Emulator HOWTO - This document will describe how to get your Linux box to connect to a generic site via a SLIP/PPP emulator, such as SLiRP or TIA. - http://en.tldp.org/HOWTO/SLIP-PPP-Emulator/
Linux PPP HOWTO - Linux PPP HOWTO at Linux DOC. - http://en.tldp.org/HOWTO/PPP-HOWTO/
X-ISP - XForms-based interface for pppd/chat. Features: supports multiple dial-up accounts, PAP/CHAP login, easy configuration of many other PPP options. - http://xisp.hellug.gr/
The Diald Home Page - The name Diald is an abbreviation of Dial Daemon. Diald's only task in life is to make it transparently appear that you have a 24 hour a day connection to the Internet over a SLIP or PPP link. - http://diald.sourceforge.net/
How to Hook up PPP in Linux - ISPs differ in their PPP authentication methods, and few of them even understand what technique they actually use. This document may allow you to set up without their help. It also discusses general information you'll need to understand about PPP in Lin - http://axion.physics.ubc.ca/ppp-linux.html