When will we see more code released under open source licenses?
Over time, more of the code that makes up Android will be released, but at this point, we
have been concentrating on shipping an SDK that helps application developers get started.
In short: Stay tuned.
Why are you releasing the code under the Apache License instead of GPLv2?
One of the best explanations for the reasoning behind releasing code under Apache2 can be found in a ArsTechnica article by Ryan Paul.