My partner bought be a Logitech Wireless Music System which I've been using for a couple of days now.  It retails for A$249 but if you shop around you can pick up one for as low as A$160.

I had read a number of lengthy reviews of this product, but there really isn't much to review.  You plug the Music Receiver into your amplifier and the USB Music Transmitter into your PC and all sounds will be sent to your amplifier.  It's that simple.

One of the reviews I read criticised it because all Windows sounds went to reciever, but if you install the supplied software you can easily configure it so just your multimedia applications will send the sounds to the receiver.  The software could have benefited from using a Wizard to configure this for noobs, but it's pretty easy to figure out otherwise.

Another review I read said that Wireless Music System only works with Windows Media Player, Winamp and iTunes.  This is incorrect also.  The supplied software can automatically configure Windows Media Player and Winamp to send sound through the transmitter, and whilst it lists iTunes it only provides instructions for manual configuration.  But the transmitter appears as a soundcard on your PC so any good multimedia application can be manually configured to output sound through it.  I'm currently playing Last.fm through it.

The Wireless Music System also comes with very small and very basic remote.  You won't be configuring any playlists with it, but once you've created a playlist on the PC you will be able to start, skip, pause, and stop playback.  You don't need software to use the remote provided your multimedia application supports multimedia keys.

Until now I've been using my iPod to play music through my amplifier.  From now on I think Winamp will be my knew CD player.  But my Wireless Music System will mostly be used to listen to Triple J (I live in a Triple J black spot of town) and especially Last.fm.  Last.fm doesn't yet work with the remote, but I believe support for multimedia keys is on their to do list.