Initial details can be found on the X.Org Wiki. For easy convenience of developers, it's falling the week after the Linux Plumbers Conference in Santa Rosa. (It's also falling right before Oktoberfest, in fact it ends the night before the start of the yearly Phoronix pilgrimage.)
As always, I'll be posting my notes from the X.Org conference on Phoronix. There will also hopefully be audio/video streaming.