I've been using record narration in powerpoint for a few years now to record lectures (live) for distance education students.

Amongst several gripes I have with the chnges in 2010, the worst problem is that the audio in recorded slide shows will not work at all in older versions of powerpoint. The odd thing is, I am sure it was working last year before our uni switched from XP to windows 7 (64 bit). From memory, it worked fine under XP.