On the SimCity official site, a developer blog has been set up. The first entry in the series was posted the other day, talking about some things inside the Glassbox engine (with accompanying video). It's a good read, and the developer blog is worth keeping an eye on.
Some older users may remember that something similar was done for SimCity 4 before release (unfortunately, they are no longer around). Personally, I'm quite pleased that they're taking the effort to explain game mechanics so early in development.