Microcredit is a financial innovation which originated in developing countries where it has successfully enabled extremely impoverished people (mostly women) to engage in self-employment projects that allow them to generate an income and, in many cases, begin to build wealth and exit poverty. Due to the success of microcredit, many in the traditional banking industry have begun to realize that these microcredit borrowers should more correctly be categorized as pre-bankable; thus, microcredit is increasingly gaining credibility in the mainstream finance industry and many traditional large finance organizations are contemplating microcredit projects as a source of future growth. Although almost everyone in larger development organizations discounted the likelihood of success of microcredit when it was begun in its modern incarnation as pilot projects with ACCION and Muhammad Yunus in the mid-1970s, the United Nations declared 2005 the International Year of Microcredit."
Also, here are few more articles about Mr. Yunus---

http://jcgi.pathfinder.com/time/asia/2006/heroes/bl_yunus.html
http://www.time.com/time/magazine/article/0,9171,1546339,00.html
http://www.msnbc.msn.com/id/15254411/site/newsweek/