Google for a song, click to play it.
I'm not sure how long Google has been doing this, but they've got a nifty "Play Now" button when it figures out you're searching for a specific song. I noticed this just now while looking for some R.E.M. lyrics. You click the button and you can listen to the whole song via iLike.com, or check it out on Pandora or Rhapsody. Nifty.
