This is a very nice idea that was promised long ago but has taken many years to materialise. Devolo have launched a range of products that will give you an ethernet network in your house by using your mains wiring to carry the data around.
Setting up a network is a simple as plugging in an adapter at each location you want an ethernet port.
Using the Homeplug standard, the devolo units will provide an RJ45 port out of a plug socket (the downside being of course that you lose the plug socket – something that’s already a scarce commodity in my house!)
There are two variants of the adapter – one that provides 14mbps (why bother?) and another one that gives a more useful 85mbps data transfer speed.
Other adapters available from Devolo can carry audio and USB data using the same principle (although the USB one is linked to a low speed eithernet module – I guess they couldn’t get the bandwidth out of the power line for high speed ethernet and USB)
The adapters are available in the UK from BroadbandBuyer.co.uk