iPhone users had to wait a while for fully functional app for the iPhone from Sling. The SlingPlayer finally surfaced, but at first, it lacked the ability to stream over 3G.
Sling is now working on a new app specifically for the iPad that will offer higher resolution streaming of content. Sling also states that it is still working on the Android app and the application will land this summer.
The SlingPlayer Mobile app for iPad will reportedly take advantage of the larger screen with higher resolution video. Sling also states it is working on moving to the H.264 format.