You will surely be able to use G Maps (though I personally think Ovi Maps blow Google Maps out of the water).
As for the other Google mobile apps, I really don't know. I know there are a few that Symbian already had supported but not that many.
If you're asking whether you can synchronise your Google mail, address book and calendar with the Nokia, the answer is yes. Google provide its subscribers with settings for what amounts to a free Exchange server for mobile users, and everything synchronises perfectly well.
Well...not quite as perfectly as MobileMe synchronises with an iPhone, but well enough to call it perfect. :-)