If satellite TV is being streamed from a place that has paid for the service, it is not illegal, but if the service is being watched from a place that has not paid for it, it is considered stealing. The process of viewing free satellite television is commonly referred to as "pirating."
The process of stealing the stream from a dish provider requires making use of an emulator, dish and receiver. The emulator must contain the proper software to de-crypt the video signals, which are sent to the receiver. This whole process is considered a form of fraud or theft, and is illegal.