Don, you may be interested to know it IS worth getting a tool (whatever that may be) to do what you described above.

I used an App on my iPhone called MIDOMI - Kind of like the Shazam app you see in the ads (the one where they hold the iPhone up to the speaker and it tells you what song it is) except Midomi is a lot more flexible. You can type in the name of the song, hold it up to the speaker, or just HUM the melody (yeah, it actually works) and the app will tell you the song, alternate versions of the song, Discography of the Band(s) who did the song, an option to buy the song, or just to stream it from Youtube.

So, Midomi REALLY helps me.
Before that app (and the iPhone) I would never be able to play almost ANY song for somebody. Just last week an elderly guy came up to me at a gig and asked me for a song I'd never heard of, but meant a lot to him. I got him to sing the song into the iPhone, and sure enough, it came up with it! We couldn't play it for him live, but I just streamed the song from youtube, plugged the phone into our PA system, and the guy got up with his wife of 40 years and danced around the room with a big ol' smile on his face! (It even sounded pretty good!!)

That's priceless - it makes you the ULTIMATE DJ - there's (practically) nothing you can't get for someone, new OR old, live - at a gig!

Btw, all that streaming cost me nothing as I was leeching some Wi-fi from the Venue, because I used a great Wifi finding app that cost me just $2.

Life is good.......