There are reports today of the (possible) news that Google Earth is to have sound files embedded so that as you are viewing the satellite imagery you can listen to suitable sound effects along the lines of; the sound of the sea; jungle noise; deserts winds, etc, (rather than the M25 at rush hour). This sounds like a fantastic, if slightly gimmicky, way to add interest to the service.
We will wait to report on the official announcement which is due at the end of the month at the "Where 2.0" web event in the States, but in the meantime we can recommend a visit to the website of the company who are supposed to be supplying these sounds – Wild Sanctuary (hyperlink below) - has a worldwide collection of sounds that represents over 3,500 hours of wild soundscapes and covers nearly 15,000 species of animals, birds and insects.
If you click through to their online store (with the soothing sounds of birdsong playing as you do), they have some astounding natural ringtones available ($2.99 each) but all available to hear as a free preview. The spadefoot toad, orangutan and desert tortoise are particularly good, but truly recommended if you want to scare the bejesus out of your dog/cat/small child/fellow commuters on the tube is the Clouded Leopard's growl/roar, quite hair-raising on a half decent computer sound system.