Android is an open-source mobile phone platform developed by Google and the Open Handset Alliance, announced on November 5th, 2007 and released on October 22, 2008 with the T-Mobile G1 in the USA. It is an open-source operating system based on Linux, and is designed to be embedded on mobile devices adhering to the Android standard. The most significant features of Android is that it carries no licensing free to be used by phone manufacturers and is an an open platform that third-party developers can easily create applications for using standard API calls implemented by the independent hardware manufacturers. Android comes equipped with many built-in applications including dialing, messaging, media playback, and with immediate availability to mobile versions of Google search, Google Maps, and Google Products but the intention is to have other developers create new applications in the future. All applications are given equal weight, such that even the basic dialing app can be overwritten. An SDK and an NDK are freely available for download, and so developers can get started developing for the Android platform. The Android OS is used in handsets manufactured by HTC, LG Electronics, Motorola, Samsung, Acer, Huawei, and Sony Ericsson, and Android devices are available on all national carriers in the U.S. (T-Mobile, Verizon, Sprint, AT&T). The current version of Android is 2.1 (Eclair), released on January 5, 2010, and version 2.2 (Froyo) has been announced at Google I/O in May 2010.