Power line home networking

[JuggaloBrotha]

Does anyone have any experience with using the power outlet for home networking?

I see these on buy.com this week: http://www.buy.com/prod/zyxel-pla-40...tml?adid=17070

I'm wondering what the range of the signal is and how it actually works. My grandparents (their house is just across the street) shares the same meter as me and I'm wondering if I could plug one into an outlet at my house with the network cable connected to the router then plug the other into an outlet at their house with the network cable connected to their computer.

Both of our houses have main feeder lines from the main breaker on the pole connected just after the meter. Here's a diagram:
Attachment 75847
Would the network reach their computer from my router using a power line network like this? Or would it be a waste of money for me to try?

Also does this stuff interfere with other electronics connected? ie would it mess up any appliance in my house, I'd assume not otherwise these things wouldn't be developed and sold.