I have the "Old Skool" version of this from Netgear.... I can connect my DSL Router (internet into the house) into one of the Netgear Powerline adapters (transmitter) that is plugged into a standard (USA) wall outlet. I can then plug the other powerline adapter (receiver) into another wall outlet in the house and have internet / network access at that wall plug without running Ethernet Cable ( Cat5 : looks like but is NOT a heavy duty phone line).

I have seen the 'Newer" version which uses a similar wired connection powerline transmitter with a powerline receiver that has wifi instead of a wired ethernet connection.

IIRC everything I have read about the Wifi version is that it is not very secure. You would be better off with a regular Wifi router..

NOTE: This is VERY different than Broadband over Powerline ( alluded to by RobbH) where the Internet into the house is run through the BiG A%% wires that also bring in your electricity. This is meant to be an alternate to DSL (Phone Lines) or Cable internet (same as Cable Video). I don't think it every really took off...

Long answers to what I hope was your question...

M