Amazon and Newmarket both have listings for the Synecdoche script book, which they say is currently slated for an October release. So you can probably extrapolate some other info from that, ie. the actual movie's approximate wide-release date. Or not! As the case may be. I don't know. I just work here. Thanks to Paul for the heads-up.

Update: New Synecdoche stills over at the Cannes site. Seems it'll be premiering there on the 23rd. If you happen to be in that neck o' the woods during the Festival, do let us know if you see anything worth mentioning. Thanks to Luke.