Since the Xbox forums have been redesigned, I can no longer find threads on Final Fantasy XIII freezing on the Xbox 360. There were quite a few people affected by this problem, but I'm not sure if Microsoft ever officially responded in those threads. Moreover, with the removal of the threads, there seems to be no further conversation among Xbox owners about this pretty serious issue.
For the record, my post on this problem is located at http://www.ardamis.com/2010/03/12/final-fantasy-xiii-freezing-xbox-360/.
As far as I can tell, this will be the only post on the forums about this problem. If the forums are not a good place to maintain a record of people's difficulties with the game, I'm happy to keep the torch lit over at http://www.ardamis.com/.