The remote for the new Dish boxes use ZigBee. Is this the same as the XBee modules?
Obviously not a high powered solution, otherwise you’d be changing someone else’s receiver 2 miles away 
You had me excited there for a moment. I thought you were saying Dish was moving their own remotes to Zigbee. Zigbee is a protocol that is used over XBee. It would be cool indeed to have that kind of control over my satellite box.
ZigBee is a standard protocol maintained by the ZigBee Alliance. All devices that use this protocol should be compatible with each other, like with bluetooth. Therefor you should be able to communicate using Xbee modules. The question is what is possible using the protocol.