Yes, the weemote works with most Dish Network systems. The only caveat is that the Dish Network receiver box box must be able to accept infrared commands (IR) and not radio frequency commands (RF) only.

The way you can tell if your receiver uses RF remote control is the fact that you can take your original remote control and not need to point it directly at the receiver to operate it. With RF remote control, you can be completely turned around from the receiver or even in another room. If your original remote still works under these circumstances, then your receiver uses RF based remote control.

Some Dish Network receivers actually use a dual-tuner system, where the location of the actual receiver unit operates using IR remote control while a remote TV in another room is controlled using RF remote control. In the case of a dual-tuner system, the weemote will work with the TV directly connected to the receiver but not to the remote TV in another room. 

Keep in mind that some of these units can actually support both IR and RF signaling. You can check your receiver by going into the setup menu to see if it supports IR. You may need to turn this feature on to allow the weemote to communicate with it. 

To reiterate, the weemote supports IR based remote control only.