Better late than never at all. Rockstar Games has announced that L.A. Noire will appear on PC this fall.
This time around, Rockstar Leeds is handling development. An official blog post promises keyboard remapping and gamepad functionality, in addition to better graphics and support for 3D.
I'm not so sure I want that last feature, based on some of the bodies you have to inspect in L.A. Noire. Even still, this will be a very good addition to the platform. (Please be a good port. Please be a good port ...)