I'm working on a post about cutting the cord with your Apple TV, and my best discovery so far is that I'm able to watch the wide range of programming that Sling TV offers for just $20 per month via my Apple TV. The service includes ESPN, ESPN2, AMC, A&E, History channel, TNT, TBS, Disney channel, Travel Channel, CNN, HGTV, Food, and more. This can be done in two different ways: mirroring your iPhone or iPad using AirPlay and using Sling TV as your credentials for the WatchESPN app.
WatchESPN
If you're a sports fan, one of the hardest parts about cutting your cable or satellite TV service is the loss of sports programming. I've long been reluctant to pay the typical $100 per month cable bill, so I was thrilled when I found out that my Sling TV credentials can be used to watch content via the WatchESPN app for Apple TV. I'm able to watch all the programs offered by ESPN and ESPN2.
Once you're signed up for Sling TV's service (a free seven-day trial is available), then you download the free WatchESPN app to your Apple TV and open it. The app will give you a website address and a code. You'll need to go to that website via your iOS device or computer and enter the code. Then the app will ask you to select your TV provider in order to get access to the content available. Select Sling TV from the list, and you're set.
The app offers featured content, as well as letting you sort by sport and by channel. Note, though, that the app has a range of channels, such as various college basketball conferences, that aren't available to you. You'll only be able to access the ESPN and ESPN2 channels.
Sling TV app and AirPlay
Although ESPN is a big draw, Sling TV has a range of additional channels. If you want to watch those on your Apple TV, you'll need to use mirroring via the free Sling TV app your iPhone or iPad. Open the app, slide up from the bottom of the screen to view the Control Panel, and then select AirPlay, select Apple TV, and turn on Mirroring. I've found that the app was a bit balky when using mirroring; but if you're patient, it works fine.
One nice feature of Sling TV is that you can come and go as you like. If there's a sports event you're particularly interested in watching, you can sign up for a month and then cancel. After 30 days, your service ends. Then if you subsequently decide there's something you want to watch, you can log into your account and restart your service.
There's no word on whether Sling TV will eventually offer an app for Apple TV. The only statement on the Sling TV website is that currently there's no app available and that people have the WatchESPN option.