I've seen it, didn't really pay much ttention to it, until this.
The thing I noticed first, is it's enhanced by Google and powered by AOL search, which in turn is another Google API.
My conclusion is that it's just an Google interface dressed in a Winamp "skin". So I'm guesssing, and can't confirm because I haven't used it, that it's going to return the same results that Google would return, with Winamps optimizations to them.
Nothing more than another SEO, 'cepting you get your results poisoned by Winamps preferences not yours.