Spider Robinson’s treatment of a Heinlein novel, Variable Star, is being released September 19th. Spider is one of the few writers I’d trust with this kind of thing (though John Varley would have been my pick).
Charles Stross has another Laundry novel out in November, The Jennifer Morgue. Supposed to be a James Bond pastiche with a lot of Lovecraft and probably geeky tech mixed in.
Robert Charles Wilson has a follow-on to his Hugo-winning Spin out next June, titled Axis. Spin is one of the best pieces of SF I’ve read in a while.
And Emma Bull comes back out of seclusion? retirement? playing lots of music? in July 2007, with Territory. Another author who has never written a bad book. Well. almost (and that one was with another author who I don’t like).