Thanks to Ax for mentioning this on our forum: Blue's News reports that the Gathering of Developers annual fan calendar contains a mention of...dum dum dum...
Myth III: The Wolf Age.
The developer will be Mumbo Jumbo. There's a two-paragraph description of Myth III, which you can find either at Blue's or in our forum thread. It's a little discouraging to see Myrkridia and Oghre misspelled repeatedly, but we can hope for improvement.
Oh, and the official Myth III site will apparently be myth.godgames.com, although it's not yet active.
Update: According to Stomped, an announcement about Myth III will be made at Macworld next week. Also, October isn't necessarily the release month; I read that wrong. Thanks to the FutureMyth guys for catching that. :-)
- Forum: Myth 3 Announced?