J.K. Rowling has a rather charming web site that she actually seems to be writing herself (one sign that marketing doesn't control the site is a rare flash of rational web design: a very usable text version of the site). While reading it I was surprised to see that she had gotten the title of the first book in the series wrong. However, it seems that in the U.K. the first volume is called Harry Potter and the Philosopher's Stone (rather than "Sorcerer's Stone"). The same is true in Germany and in Japan (the latter at least according to poor Babelfish's garbled translation, "Stone of Halley [untranslatable] and wise man") although not in France, where it's just called Harry Potter at the School of the Wizards</a>.
Allegedly, many scenes in the movie were filmed twice, one with each phrase. How strange. Were they assuming that Americans were less familiar with alchemical lore?