Recording off the sound card is what I would do. Theres a free to try program made by High Criteria called Total Recorder that is very good for this. It's only 12 dollars to buy.
It lets you record incoming audio as well as outgoing audio. Anything that passes through your sound board, it can record. It's always worked well for me.
http://www.download.com/Total-Record...ml?tag=lst-0-1