Assuming the Dish receiver you're getting is DP compatible, that's it.
One question - why not just go buy a Dish 500? It'll be just about as easy to install and makes 2 satellites available.
OR, if this is for a 3rd satellite being added to a Dish 500 system, then you'll need to get a switch - either DP21(s) or DP34 depending on the number of receivers. If the 3rd satellite is to get your locals, I believe Dish will come out and do that for you.