I did a short guest post on the blog of the LEEF Conference on why game feedback is different from feedback in learning. You can see it here:
http://leefblog.com/2010/03/learning-games-and-sims-all-about-the-feedback/
The LEEF (Learning and Entertainment Evolution Forum) Conference is shaping up to be pretty interesting, too: http://www.harrisburgu.edu/LEEF2010/index.php