Lead designer of D&D 5E, Mike Mearls, has made the announcement at the Wizards website.
I think this is great. I am guessing it would be pretty rules-light and deliver on the designers’ promise of players being able to scale the system’s complexity.
The Pathfinder Reference Document is also available online for free, but it’s not in an easily-printable format and it’s meant to be more of a reference and not an introduction to the game.
This, combined with the power of D&D’s brand, D&D’s own Starter Set, and with Pathfinder’s excellent Beginner Box, should together help expand the reach of the hobby and thus the player base for both D&D and PF.