You forget how well Sting can sing (stick a curly wig on him and he could be Cleo Laine). Actually, getting Sting to sing pretty much his entire interview was a stroke of genius by Fallon; he didn't have a chance to drone on about all the egomaniacal stuff he usually comes out with.
By way of an example, look no further than his website, Sting.com, which says stuff like: "Sting is the pop world's ranking intellectual and musical sophisticate." In fact, the homepage features a "QUOTE OF THE DAY". Today's quote is "When I was 25 I knew everything. I was completely sure about everything. Now I know far more - and yet I'm much less sure. For me, it's wonderful to live in that paradox."
Anyway, behold the far more entertaining world of "Sting Tones", which sound even better than the real thing. As for the voice mail he records for a "fan", it's not exactly personalised, but that's probably because yer man's hungarian with a rather tricky name...
Why was Sting recreating ring tones on The Tonight Show? He's currently on Broadway and needs to sell more tickets.