I would like to use two ethernet cards in one computer, one card for internet (connected to a dsl modem) and the second card for a home network (connected to a ethernet switch).
Is it possible to do this, and if it is, how do I configure everything?
Yes it can be done. Just install each card as per its own instructions/disk .
Then when you configure your dsl modem it should ask you which network adapter to use. Pick one and finish modem install.
Same as when you configure your home network , it also will ask you which adapter to use. Tell it the other one and all should be well.
We have up to 4 PC's surfing @ once. But when I had mine set up like you want , I always had to have the main PC first to surf from my laptop in the bedroom. Then I broke down and got a Ethernet Broadband Router. Now you can fire up any PC one at a time and surf. And you wont need the second card in your main PC.