There are singing groups that will do surprise visits to houses. Do you mean as a joke, or for a nice gesture? If you just want it as a joke, I'm sure somebody you know will be willing to sing on a doorstep for a little cash-in-hand, but if you were wanting a more professional, serious gesture, you could try your local church choir, barber shop quartet, or ask around to see who did caroling at Christmas time. There are people who do this, it's just the matter of finding the right group in your area.
You mean a singing telegram? It's possible there are still some services like that available, but I think, for the most part, they phased out in the 80's.
You can look up "Singing Telegrams" online or in the phone book. In most large cities there are services that will do this for you.