I have two direct TV boxs with ethernet connections.  You can plug them into the network but it really does nothing for you.  I had read on the forum groups they were testing networking in select areas.  Like Tivo, if you record a show on one box you can play it over the network to the other box.  I called Direct TV to ask to be on that beta, but no one would help me on that.  I figured that if I plugged them in when they role the beta out to more people they might see that mine are ready to go.  Well I turn on my Direct TV and they let me know that I am in the Direct TV on demand beta.   If you know anything about satellite TV, nothing is on demand.  Everything is down stream.  So how does it work?  Well you actually download your on demand shows over the internet.  So you pick the show you want to watch and it starts to download it.  How long it takes before you can really watch depends on your broad band connection.

I used to have comcast cable and it had on demand as well.  Everything I watched on that was very heavily compressed.  It was so bad that I couldn't watch it.  It was like watching video off a CD ROM game from 1990.  The visual quality of the Direct TV on demand video looks the same as the standard def video they broadcast.  There was a section for HD content but there was nothing in there.  I will have to check back later on that one.  One other feature is you can pick pay per view movies to download but they don't charge you until you watch it.  You can download it now and it will be ready when you are ready to watch it.  I have a xbox 360 with movie downloads but I hate that you have to pay up front and then wait.  If you want to watch something that evening you have to pick it that afternoon to start downloading.  Direct TV has also made it really easy to find the on demand channels.  It just has a one in front of it.  For example the history channel is on 269.  Want to see what is on demand for history channel, just tune to 1269.  Easy.  

My only complaint on the direct TV on demand is the audio level.  It is very quite.  You really have to turn in up to hear it.  Which sucks when you switch to something else because then you just get blasted.  Its beta so hopefully they will fix that when encoding the video.

So I still don't have networking video which I was hoping to get by plugging in the boxes to the network but I will take this on demand stuff till then.