Now this is an annoucement and a half. Or as the Free Our Data blog puts it "do we smell victory? Hell yeah". Or you can take the rather more restrained announcement directory from the Ordnance Survey itself.
Nobody quite knows what this means yet. Is it access to OS maps, at 1:10,000 and smaller? Or is it access to data? Raster? Ed Parsons has some thoughts. As does the Guardian. Let's watch this space eh?