The easiest way to pipe MP3 tunes and internet radio stations round your home is to tether a laptop to a wireless connection. If you want a cheaper option, there's BT's Voyager. It's a mini hi-fi device which, apart from an integrated FM tuner, has no direct music sources. Instead, via an FM transmitter plugged into a PC's USB socket users can stream music from a computer/the web (MP3, CDs, internet radio stations) to the Voyager that can be sited anywhere in your home.
It works reasonably well, too, with the on board speakers just about loud enough to cover the background FM hiss.
Operating the Voyager is, however, quite tricky. Both the PC software and the device's interface are intimidating and there's no easy way to access or search for MP3 tunes on the player.
It may be the cheaper option, but the Voyager is not especially tasteful.
Do you need it?
Overall, the Voyager is worth a punt if you have five or six net radio stations you'd like to hear elsewhere in your home.