Nothing official, but I'm fairly certain it will work. Socket 939 isnt that different from 940, and it is confirmed dual core opterons will work in existing s940 boards with just a bios upgrade. I see no reason why S939 would be any different.
Furthermore, it is confirmed that AMD will produce a dual core Athlon (FX) product.. if that will not fit into S939, then where would it fit in ? There are not many enthousiast type of S940 boards, so that is hardly an option, and a new socket is no-no for such a low volume product, so that leaves S939 boards, or no dual core Athlon.
One last thing; depending on what you do, I wouldn't hold my breath for dual core. Unless you run some CPU bound, properly multithreading app, the performance increase just won't be there. As it is, only a few workstation apps really benefit from more than one core/cpu, and precious few consumer apps. And in spite of what some will tell you, it will take a very long time before we see usefull multithreading in games and plenty of other apps. Media encoding could benefit substantially though, but that is about the only consumer grade app I see that would warrant dual core in the foreseeable future.
Just my 2 cent
= The views stated herein are my personal views, and not necessarily the views of my wife. =