LyricFind.com has one goal in life:
helping you get the most from your music. We’re available 24/7, should you wake up at three in the morning humming that new Radiohead tune, but unable to untangle the lyrics. We’re here to clarify the difference between lines like “Excuse me while I kiss the sky” and “Excuse me while I kiss this guy.” We’re the web’s largest song lyrics database. And we’re growing all the time.
I did a search for just as sweet as a girlfriend can be from Robert Johnson’s When You Got a Good Friend with no success. I found room 619 from Peter Gabriel’s Biko though.