Partnerships among health care and information technology researchers and designers worldwide are creating mobile health tools tailored to local community needs and resources. Much of the hardware and infrastructure comes from developed countries of the so-called global North. From both these countries as well as developing countries in the global "South" are coming applications that enable health workers to collect and organize data, access diagnostic and treatment support, and promote healthy behavior. Most are still in pilots or demonstration phases, but their use is accelerating. © 2010 Project HOPE-The People-to-People Health Foundation, Inc.