Those things are retarded. I'd just as soon get a real equalizer and run my soundcard through it.
If it had a Dolby Digital/DTS decoder built-in, I could see it. As it is, it does nothing an SB Live! and WinAMP couldn't do by themselves.
Except for the built-in FM receivers they have. Woopdeedoo.
I believe you just run your line-out into it.