As I write this, CBC is predicting a very close minority government in Quebec.
What does this signal to Stephen Harper? A couple of things spring to mind - first, I would suspect (quite strongly) that it should tell him that Quebecers aren't necessarily all that impressed by his blatant play to bolster Liberal Premier Charest's campaign by throwing money at Quebec (nor should they be). In fact, when Charest turned around and promised to use that money for tax cuts, he actually damaged two things - his own campaign, AND Harper's claim to be fixing the "fiscal imbalance".
I'm not sure that the rise of the ADQ means anything terribly significant to Federal Conservatives. While the ADQ is not per se a separatist party, it certainly would be a stretch to consider them "federalist" either. While Boisclair sounds like a policy ally to Harper in several dimensions, I think the ADQ is appealing to what has been traditionally a "soft-separatist" vote - those who want to use the threat of Quebec separation as a political tool more than actually wanting to partition Canada.
Although Harper would be quite happy to delegate everything possible to the provinces, an isolationist government in Quebec doesn't necessarily help Harper's agenda, nor does it indicate an increased interest in Harper's notion of Conservatism for Quebecers on the Federal level.
In fact, it doesn't even say much to Dion's Liberals either, since Charest seems to be more of a Conservative than a Liberal these days.