Google recently updated their android search service (Google Now) to include more cards and tighter Google Plus integration but another new feature is different way to get into the "what's this song" query. Simply tap the voice search button, say "What's this song?", and you're good to go.
I played around with it this morning and it works as advertised although the search engine still has trouble picking up my Boston accent sometimes. No matter how "clearly" I try to speak it still sounds like "clee-yah-lee". No big deal though because the way we talk is wicked awesome, but I can see how some people with thick accents would find it frustrating to have to keep repeating things into the search engine.
So I fired up my Google music to the best Christmas song ever, The Pogues with Christy MacColl singing "Fairytale of New York" , and Google picked it up without a hitch. Next I went with *NSync's "Merry Christmas, Happy Holidays" and again the correct card showed up and gave me the option to go to the play store to purchase the song.
The only drawback so far are that you need to be on Jelly Bean (obviously) and that you can still only search songs that are already in the play store. In playing around with the "what's this song" app since it came out it's always picked up on the song I was looking for. No need to worry if it misses your song though, soon Google will be implementing their Music Match service with an for greater catalogue of tune choices.
Google is known for giving users multiple ways of getting to their desired outcome, for instance having the option to swipe up from home to get to Google Now or just tapping the search widget, and this option is no different. Also I'm someone who almost never uses widgets because I feel that they clutter up my screen, so having the option to get into this "party trick" directly from Google Now is a big plus for me.
So give it a shot and try this for yourself. It's a pretty fun feature of Google Now, which keeps getting better and better the more they update it.