splendad.com
Several months ago I heard a song on a commercial and looked everywhere online trying to find it. I finally did at SplendAd.com, a website dedicated to music that's on commercials. Didn't know there was such a thing, right? Me neither, but it's a great idea and it saves me hours of searching.
They have several years' worth of information, and it's constantly being updated, so it's a great resource when you really need to know!

