As promised, search engine giant Google has released the source code for its Android platform — the open source technology that Google hopes will be adopted by mobile application developers, phone makers and carriers alike. The move comes just a day before the first Android-powered smartphone — the G1 — is set to hit U.S. stores. The G1 is available only through T-Mobile. Google first announced its decision to make the Android source code public in November 2007, as part of a larger open source computing and software initiative.