Gamespot has the latest Designer Diary. This one is by Jason Bender, and discusses the methodology used to create the AI for C&C 3. One thing's for certain: they've come a long way from the (frankly awful) AI in Generals (and its even worse scripting interface).
The AI accommodates different play styles through customization. Simply select an AI personality that matches your style of play and you're good to go. Or, have the AI randomly select a style of play and see what strategies get served up. Customizable AI solves the age-old dilemma of past RTS games, where people with different styles of play got frustrated by the uniform tactics of the AI. A player who likes to turtle will be constantly frustrated by a fast AI rush--and vice versa. In Command & Conquer 3, you can let the computer go with what it thinks is the very best strategy, or you can give it a predisposition to use certain tactics and strategies.
They've transitioned to an XML interface that I think will help modders tremendously, and will ultimately lead to a better AI. You can read the full piece here
In addition, over at Gametrailers
, they have two new C&C 3 videos, one of the demo, and one from the story showcasing the destruction of GDI's space station, the Philadelphia.