Ooh, good idea. As a reader I always enjoy when authors post this sort of thing. To get things started, maybe you (and others) could post DVD commentaries from the past -- I know the author of Worth the Fight (can't remember her name off the top of my head) did at least one DVD commentary for one of her stories.
Also, not sure if you want to go in this direction or not, but there's a comm on LJ that's set up for readers to do DVD commentaries as they read a particular story. I'm pretty sure someone did commentary for one of mclachlan's fics (aha: http://community.livejournal.com/dvd_commentary/39393.html). Obviously that's a sort of different kettle of fish than an author analyzing her own work, and you'd have to set up some sort of author permission system, but it might be worth considering.