Aidan Moher of A Dribble of Ink reports that Tad Williams will be doing a Reddit AMA (Ask Me Anything) interview with fans on Reddit’s fantasy board on September 18th:

So, if you have anything you want to pick his brain about, mysteries of Memory, Sorrow, and Thorn, if he realizes that The War of the Flowers is his secret best work, or what it’s like to have been a direct influence on the biggest fantasy series of the decade (Martin’s A Song of Ice and Fire), now’s your chance!

The Witchwood Crown is still on track for a 2015 release from DAW Books. If you’re looking to join in the fun, now would be a perfect time to discover Tad Williams’ seminal Memory, Sorrow and Thorn trilogy, beginning with The Dragonbone Chair.

More details, such as exact times for the interview, are forthcoming.
Update: Deborah Beale, Williams’ wife, states the AMA interview will be ‘mid-day’, but she’s not sure what time zone ‘mid-day’ represents.