UPDATE - I have just got back to Italy after my vacation in Canada. While in Toronto I took my Macbook to the Apple Store and without batting an eyelid, they changed the top case at no cost. They also gave me, FREE, an old never used charger that they had, as the new stile ones with new attachment, did not work on my laptop. Apple Italy and Apple Europe (Ireland) refused to do anything about the crack or the charger!!
Glad they helped you out. That is the way it should be.
BTW, is the blackbook less prone to cracking, is the topcase a different material? I have the early 2008 model and still no cracks. I have AppleCare until next year. Meanwhile, two of my friends' whitebooks 2006 and early 2008 have had cracks.