Sling just submitted the 1.1 version of Slingplayer, which we reviewed here, to the App Store. It's going to have 16x9 widescreen, better remote, a faster connection for channel changing and remote control, plus DISH integration.
The DISH stuff is new, and will connect directly to the DISH receiver to "draw" the guide on the iPhone instead of just streaming a picture of the guide. It also has search and filtering features "that are not possible even when sitting in front of your TV." We'll let you know when the app's live.