Wireless Audio not for the Common Man
As with all wireless systems, this one isn't truly wireless; but it is pretty close. You'll need to get power to the receiver/transmitter unit using that old standby called a powr cord (a good installer can hide this part - especially if you choose the wall-mount option), and the local room speakers will have to be connected to the receiver by speaker wires. The connection with the main system is wireless, at least. The receiver/transmitter itself can be wall-mounted using one of two different brackets, or it can be placed on the floor, a shelf, or in a bookcase.
A BeoLink Wireless 1 unit can be used as a transmitter or receiver. One transmitter will deliver audio to up to seven receivers, and the system will handle a maximum of three transmitters and a total of 21 receivers. B&O says a transmitters and receivers can be placed up to 100 feet apart in a typical home - or up to 330 feet apart when used outside.
The system uses the 2.4 GHz band with special B&O technology that eliminates interference with everything else in your home that transmits wanted information or undesired garbage in that band.
You can find BeoLink Wireless 1 units in Bang & Olufsen stores. (Don't be looking for it in Circuit City, folks, or you'll get some really strange looks.) Suggested MSRP is $450 for each receiver/transmitter unit. They're available in black or white.