The reason it is just now showing in your PS3 is the software update this week.
There are no announced plans to allow the media to be played on anything but the DirecTV2PC software...yet.
I don't know if we'll ever see it playable on a PS3 or Xbox, but it could be possible if they wanted to. More likely would be the ability to play media to another DirecTV HD-DVR, commonly called multi-room viewing.
Again, this recent software release enabled the receiver to support DirecTV2pc, that is why you are seeing the server on your PS3, or PCs, or other networked equipment.