Op-ed by NICHOLAS D. KRISTOF Bill Gates=E2=80=99s Next Big Thing=20 A peek into a letter Bill Gates will publish on Monday. He=E2=80=99s not onl= y going to do more for health and development in the poorest nations and edu= cation in America, he is calling for your help, too. http://www.nytimes.com/2009/01/25/opinion/25kristof.html?ref=3Dopinion ******