A post ago I talked about that Google is in the process of developing a new build system for application developers using Gradle which is in fact Groovy based. Since there only at version 0.2 right now that may be a slight wait as they still have IDE ADT integration, RenderScript support, NDK support, ProGuard support, Lint Support, emma support, and JUnit report.xml and html generation. But, one should still start getting an idea of how it works so some resources:
New Build System Concepts
Using the New Build System
Gradle User Guide for 1.2
Gradleware.org also has a free book if you register and the link is on the front page of the gradle.org site. For those who want to play with it now, the current alpha release is in the maven repo under android tools and its current version is 0.2. Its not the gradel android plugin at github:
Maven repo new Build System Gradle Android Plugin
So when will we see it in the ADT plugin or full sdk? Not sure, it be a nice holiday present if we get it before the last major holiday of this year.