How does directv do that?

DirecTV has their Spot beam up and fully running this is how they can serve so much from one satellite.

Dish Network is in the process of turning on its first spot beam TODAY!

This means that the local channels will only be broadcast in the areas for which they are intended instead of all local being broadcast nationaly as is the case now.

Now I see what ya mean by spot beam.... So we can look for Dish to add some new channels.....

I think they make "throw us a bone" in June with Discovery HD and maybe one other channel. But I would not expect more untill Echostar 8 is up and fully operational.

They're doing it from one slot with all available transponder licenses, not one satellite.