The DU (yes, I know) thread has some links and this official blurb:

"Accompanied by Zanzibar's First Lady, Shadya Karume, Mrs. Bush first visited the Al-Rahma Madrasa, where the two First Ladies met with school children and their teachers. The Madrasa is one of several pre-schools scattered around various villages in Zanzibar that have received over $200,000 this year through grants from the U.S. Agency for International Development. The funds are distributed through the Aga Khan Foundation to improve the quality of education by training teachers, especially in English, math and the sciences. The grants have also allowed more children to attend pre-school, who otherwise could not afford it. At the Al-Rahma Madrasa, the number of students this year increased from 55 to 67. The students greeted Mrs. Bush and Mrs. Karume with songs in English and Kiswahili."

Maybe they're the good kind of madrassas and not the, you know, foundries of terrorism kind of madrassas.