The game will be spearheaded by John Knottenbelt while Introversion co-founder Chris Delay "[begins] work on other new projects" (console titles? Subversion?). Knottenbelt mentions there will be graphical improvements from the game, though it's unclear if he's talking about the recent Vista upgrades or something beyond that, and a new formation mode, "which will let you organise your Darwinians into ranks to create massive armies."
Details are sparse currently, though Introversion is expected to make a few announcements at next week's Game Developers Conference. Multiwinia is being planned for a 2008 release.