I am trying to build a project in which I want to transfer data through existing power outlets in a home through power lines while simultaneously using those outlets for power supply also. My question Is it possible? and if yes where and how can I explore more about this topic. something like this http://www.tp-link.com/en/products/details/?model=TL-PA4020PKIT
X-10 is a system developed nearly 40 years ago (1975) which is designed to send control information over the power line to turn devices on and off, etc. It consists of controllers (transmitters) and receivers. Being so old, you can find hundreds if not thousands of devices on eBay that you could hack. Of course you can also buy new ones too from many suppliers.
There is even a library for Arduino that allows it to send and receive X-10 commands.
And here is an application note showing how to do X-10 with a PIC16.