Try this:
http://www.roaringpenguin.com/en/pen...oducts/rpPppoe
It's PPPoE software for Linux, specifically for DSL 'modems'. If you'd like a (cheap) hardware-solution, you could always spring $50 for a small home-network router, which will get the Internet/PPPoE connection going for you. It'll also provide you with an internal DHCP server, and basic firewall stuff too.
Just a thought...I've never used that software, though, but a friend of mine has, and it worked fine for him.
