This is my personal view of the problem. I think sending NGO's out to Africa is a very very bad idea. It will perpetuate Africa being the undeveloped mess it is and continual subservience to the western world (unless that's the plan of course). If people really want to help, the best first step is to let Africans try their own ideas first.
First, my background: I was a professional mathematician from Africa doing research in Algebra, now working is computational finance.
In my country, the problem is not so much with the education system. The biggest problem, like all problems in Africa, are the powers-that-be. Unfortunately aid to Africa only exacerbates the problem.
The high school education syllabus was first rate, covering a far wider ranger of mathematics than the US syllabus. We had math clubs, magazines etc.. Every year the undergraduate system produced bright math students with potential. I believe my university produced 10 to 15 math honors students, the vast majority who went for higher degrees overseas. Based on my undergrad education I was able to ace US qualifying exams, that's how good the system was. One of the biggest advantages we had was that European and American professors used to visit our university during their summer breaks. I got to meet many great mathematicians that way. Stupidly, the university has now adopted the US calendar just to look "developed".
The biggest problem is this: The people in power want to exploit the everybody, so after doing an undergrad in math the only work available was teaching in rural areas for next to nothing, unless you could get a way out.
My personal belief is that EU and US aid is a very bad thing. It perpetuates the beggar mentality of Africa (unless that's the plan of course). All those scholarships given by the western world are distributed to the politicians' kids. The truly deserving are left with nothing. I saw this personally because I was one of those who tried to get a scholarship and failed for bizarre reasons.
I had really wanted to go back when I finished my PhD. The system there made it not worthwhile. I would become and overworked underpaid professor. so I chose to remain in the US.