I guess I don't mind singing, although I wouldn't say that I'm really all that great at it. Mediocre, perhaps. I feel like I used to be better, but I'm just so out of practice with it.
As for letting others hear it...nope. Not happening at all. Way too self conscious about that to even consider it.
Although actually, I guess there have been some times in stores when I hear a song I like, and I end up singing quietly to it and don't mind as much who hears it. That's most definitely an exception though. :D