The first step is to see if your card is detected by default. If not, you'll have to tinker a bit and either hunt down a linux driver or use something like ndiswrapper. The chances are pretty good the card will be up and running from the get-go, unless you've got one from broadcom or somebody else who doesn't have great linux support for their stuff. After that you can take a peek at two packages, pppoe and pppoeconf. The first of those is the driver for pppoe connections, the second is the initial config tool used to set your connection up. I haven't used either of those so I don't know how good they are, but that looks like the way this sort of thing is usually done.
Do not meddle in the affairs of archers, for they are subtle and quick to anger.