Google has added extra info at the top of its search results for identified artist/band names, CD titles, and the like. The search engine has been doing similar things for other identifiable search tokens such as phone numbers for a while. Music searching, while popular, is often less distinguishable from regular search keywords. The links Google provides include aggregated links to big-name music sellers such as Amazon and iTunes, as well as related sites (artist news, photos), and a link to the specific music search engine http://www.google.com/musicsearch.

Mostly what I expect is that this will mean the rich get richer, as Google will drive sales to the big-name online sellers, though they do include a link for any music seller to request to be listed. There does not appear to be a comparable way for artists to get listed - presumably Google wants them to continue buying Adwords.