Using a apple tv box as a second monitor to your osx machine I've heard that you can use as ipad as a second monitor to you macbook by using software like iDisplay.

Is it possible to use apple TV in a similar capacity?

If so then:
a. Which software do I use?
b. What types of appleTvs will allow that?

Thanks.
This functionality is due in the fall with the next OS X version.  You'll have to wait a few more months.