The SlingCatcher is the correct device to use in order watch the Slingbox content on a TV. Some units are being sold by third party stores, so maybe you can purchase one of those.
You can connect an Apple TV to the Slingbox, but that will only send the content from the Apple TV through the Internet, in order for you to view it on a computer, it will not work as a SlingCatcher.
For more product information, feel free to visit this link:
I have posted an Enhancement Request for this to Apple using this link:
If enough people ask for them to make Sling Player available as an app on Apple TV it should happen eventually.
I'm certainly willing to pay to use the Apple TV as a Sling Player.
I do not want yet another box hooked up to my TV, when the Apple TV should be able to handle the job well.