I’ve written a few articles about Inform7. What I haven’t ever done is record a screencast. Aaron Reed has. And he’s done a better job of it than I think I could ever do. Check it out:
Inform 7 Introductory Screencast from Aaron Reed on Vimeo.
BTW: Inform7 now has its own website: http://inform7.com. The original website is still up at http://inform-fiction.org (I don’t know if it will be going away or not). The old site is still the place to go if you want Inform6 information.