Pandora knows what you like (or will soon)

If you haven't yet tries Pandora, it's a cool music service (free) that lets you rate songs as it plays them, so it knows what you like and can play more stuff you like. http://pandora.com/

A brief overview may be found here: http://www.appappeal.com/app/pandora

And while Pandora runs in your web browser, there's a standalone player that can be used for more functions, and so you don't accidentally close it :-) Vista users can get a sidebar gadget: http://www.pandora.com/on-windowsgadget
XP users can use OpenPandora: http://getopenpandora.appspot.com/

Here's a lengthy article that describes all the work behind the scenes: http://www.nytimes.com/2009/10/18/magazine/18Pandora-t.html?_r=2&ref=magazine