Dish Network has the ability to stream your TV to your device and it is not limited to being on WiFi or having to get your internet service from them.
Yes - I have this. Quality on Wi-Fi is excellent (HD) running on my Mac and iPhone 4 - "Other" wi-fi spots and 3g...not so good.
It is fantastic in the house though...watching the contents of my DVR, or live TV outside on the deck (this was last summer).
For those interested: http://www.dishnetwork.com/receivers/vip922/default.aspx
This is the receiver you need. Dish acquired Slingmedia a few years back. If you don't want Dish Network, you could always just buy the Sling Player.
http://www.slingbox.com/go/home