since they've got time travel and Nimoy in it, it seems obvious that it will be a "in-universe" reboot. Sort of like all those reset button episodes except without that final reset button.
Now that really begs the question of what'll happen on the Trek lit front--think we'll get two separate continuities, or a whole hell of a lot of retconning to try and bring the two continuities into line with each other?
I kind of fall in the middle on this issue. I think a new continuity could be a very interesting thing and possibly even worthwhile as far as creating a successful movie and a show that will attract new fans.
On the other hand, I think the current continuity works very well as the basis for literature (both official lit AND unofficial fanfic). Not being under the same degree of time and budgetary pressures that a movie is, there's no reason, especially with resources like Memory Alpha and Beta available, that an author cannot do the research to work within the existing continuity. The intricacy is now very well suited to the written format, much like the extreme detail in the Star Wars: Expanded Universe continuity, or Tolkien's Middle Earth.
I personally say it should not have to be an either-or dilemma: why not simply have one "new continuity" for the movie, and officially hand over the old material (ENT, TOS, TNG, DS9, VOY, and the prior movies) to the writers at Pocket Book? It seems like it's been working its way in that direction already...let's just make it official.