There was a big deal about the mosquito over here a few months ago. A load of kids tried to argue it wsa against their human rights that shop owners used it for no reason.
I've been trying to find out what it sounds like - if I can even hear it - and I could, even though I'm a practically ancient 28. Having said that, I do have incredibly sensitive hearing - my boyfriend calls me bat ears. (Mind you it's not all bad - we once saved our neighbours cos I could hear their smoke alarm through the walls and we got the fire engine out.)
For those who can't hear it, it sort of vibrates the ear drum and I swear I could feel it heating up! And now my ears are ringing.
Pretty useful site though - I'll be passing it onto my friends with children!