What is the name of a large, reputable hiv/aids prevention group working in africa?

Here are 3 websites: http://en.wikipedia.org/wiki/hiv/aids_in_africa standard wiki starting place http://www.Avert.Org/hiv-aids-africa.Htm this charity uses grassroots efforts to reach people because they tend to be less corrupt http://www.Visionafrica.Org/va_hiv.Html this is an example of a small effort I am personally helping, that the us government recognizes and funds, along with methodists.