Over on 4Gamer, there's a juicy interview with Dark Souls director Hidetaka Miyazaki regarding a variety of factoids relevant to your death-craving souls. As always, the lovely Andriasang was there to fill in the gaps with a translation. Here's a brief sampling of what was talked about.
Dark Souls will be a broad game not only in terms of its areas, but its estimated play time as well. We're looking at 60 hours compared to its predecessor-of-sorts Demon's Souls, which Miyazaki put at 30 to 40.
I would say that gamers know what they're getting into with Dark Souls, but that's not necessarily true now that the audience is being expanded to Xbox 360 players. As such, it's unfortunate to report that there won't be a demo; From Software can't convey what they'd like to in such a short amount of time.
And lastly, downloadable content -- there likely won't be any based on current plans. If there is, though, expect "something interesting" using online functionality. Don't expect, however, paid in-game items.