If you are thinking of using a "balun" or wiring converter, don't bother, especially if they are "passive" (IE no power supply needed). While these devices do tend to work, they often don't work for long and create a new point of trouble to happen.
I have had rather spotty results with various balun devices, I have one in a building which provides VGA (computer video) to a pair of projectors in an auditorium using Cat5 Ethernet cable. Started out with passive ones, had two of those die within a year each. Bought a more expensive "active" (IE has a power supply on each end) and so far it is lasted a year and a half.
Another device is the plug and power Ethernet over the power lines, I refuse to buy into that one for one major reason, 120V potential on your network wire if the device malfunctions! Just too much can go badly wrong with this idea...
Not knowing how your home is setup (IE house or apartment building) it is a bit hard to tell someone the best way to go but if at all possible I would recommend simply running some Cat 5 Ethernet cable. There are many ways to get it room to room and be hidden. Sometimes it just takes some creativity but it can be done.
You are good up to 328ft of Cat5 which allows for a lot of "detours" to get the wire from one place to the other..
In my house I have a basement so it is easy to fish wires around ductwork or other mechanical equipment.
For instance my main PC is where my DSL modem/router is, I happen to have a cold air return duct under the desk. Dropped an Ethernet cable into the cold air vent/duct, drilled a small hole in the duct and pulled the cable into the basement.
Ran that across the basement and up through another cold air duct to the second PC.
In the case of an apartment building you could run the cable up and over door frames then paint the cable the color of the wall or the frame. Make it "hide" and it becomes almost Architectural "feature". Run at the bottom of baseboards and if you have carpet you can often tuck it under the baseboard quarter round.
Sometimes you just need to think outside the box..
