Wizards of the Coast has made D&D Next conversion notes available for use in D&D Encounters and in the latest playtest packet. 

Players can decide which system they wish to use--D&D 4th Edition or D&D Next--when they create characters for the upcoming D&D Encounters story arc.  The conversion notes will also be made available online for gamemasters running D&D Encounters using the new system.
The first D&D Encounters to take advantage of the new system conversion notes will be Against the Cult of Chaos, scheduled for February 6th.  This story is inspired by the classic Dungeons & Dragons adventures Village of Hommlet and Against the Cult of the Reptile God.  This season of D&D Encounters is scheduled to conclude on April 3th.
Details of WotC’s plans for D&D Next were first revealed during last summer’s Gen Con game convention (see "The 'D&D Next' Keynote").