No word yet on how this will appear to the OS, whether it will use Xinput, etc, but it's good to know there's some compatibility there. The PS3 controller doesn't work out of the box, and requires third-party software to use on PC.
The conversation about the controller compatibility can be found here: https://twitter.com/yosp/status/386257948487340032

This is good news. Nice to see Sony putting some time and possible effort into making its hardware work in other contexts. Seems that the world is getting more open in the console space, so that's a good thing.