I was about to embark on this project, so I'll look into the isolator. Noise suppression is good.
If you want to record into line in jack on sound card, head over to Radio Shack and spend $17 on a ground loop isolator. This will greatly reduce the amount of noice that comes over the wires. Really...it's a must have. Surprised CNET didn't mention it.
Sound card line-in jacks are typically cheaply made and not of high audio quality. The ground loop isolater fixes a lot of problems and is a much cheaper solution than investing in an external soundblaster audigy solution.