Entitled Project V13 (at the moment), the new game will be about a player leading a community in a devastated world by gathering resources, rebuilding and keeping their people alive. Black Isle is asking for donations to make a proof-of-concept demo. Donate $20 and you'll be a "contributing member" and apparently have real influence over the creation of the game. Here's their pitch; the serious bit begins about 2 minutes 30 in.
Why should you care? If you ever played any of Black Isle's game in the late 90s, you'll know that they still stand up as some of the best examples of their genre ever made; if you haven't played Planescape or the first two Fallouts, you can buy them today and appreciate their magnificence. And several of the original staff are involved, and appear in the video, so it might not be a resurrection in name only. Our friends at Gamespy, though, make an extremely good case for approaching with caution.
It's been a good year for fans of classic post-apocalyptic RPGs; Brian Fargo is also bringing Wasteland back. Check out Black Isle's new website for more.