One of our sources with insider knowledge of Interplay has sent an update regarding the Black Isle announcment:
You will find the Chris Taylor (Lead Designer of Fallout) and Mark O'Green (Dialog for Fallout) at Black Isle. Right now everyone is saying it's only Black Isle in name and that's simply not true. I know it for a FACT.
Just some food for thought.
Edit: Black Isle are working on a game, but I can now confirm that it is not a new Plancescape or a new Icewind Dale. I can also confirm that this new game is directly related to a game that Black Isle has done in the past. A new Dark Alliance, perhaps?