In any case, Yahoo Audio Search has a very friendly interface. Search as you would on any site, and the search results will have a play button in-line with the search results. You can click right on them for an instant sample stream. No waiting or going to ad stuffed sites.
Of course, it won’t come up with an audio sample for all songs and not for lesser known artists. Still, this is a great step in terms of the maturity of search.