Gamespy has a fairly early preview of the next in the wildly popular Age of Empires series.

It's also interesting to note that artillery is now needed whenever you wish to destroy enemy settlements. That's right: no longer will a guy with a spear bring down a town center by poking it for 10 minutes. You'll need to bring in (and protect!) the big guns.

I strongly recommend that any RTS fan takes a look, it's a nice read and has a number of very nice screenshots included.