But what libraries are available to learn from? I'm on OS X. OpenAI.com seems to be more in planning than implementation, currently.

Companies like Apple, Facebook, etc are using AI more and more, what are they using?

Self-driving cars (and even tractors) are using AI this must be in house developed. GeoHot developed a slef driving car, literally in his garage.

There must be libraries to help get started for those wanting to learn and not write from scratch.