Actually, I believe you will only need one box or the other or a newer DVD player.
These boxes hook to your internet connection and stream the media to your tv as you are watching.
If you want to see it go to Google.com/tv or do a free month of netfilx.
There's money to be made and everyones jumping on the wagon. Be careful as some are sure to fall off and be left in the dust.
I believe any of the streaming sites will connect with your PC as well as a set top box.