Roaring Penguin Software (PPPoE) - http://www.roaringpenguin.com/products/pppoe PPPoE (Point-to-Point Protocol over Ethernet) is a protocol used by many ADSL Internet Service Providers. Roaring Penguin has a free client for Linux systems to connect to PPPoE service providers.
The whole PPPoE World for Linux - http://www.suse.de/~bk/PPPoE-project.html Index of all available PPPoE Information for Linux
Linux and T-DSL - http://www.datenhighway.com/adsl/ How to use Linux with German T-DSL.