You might want to check out this company http://www.realgap.com/ they have loads of volunteer programs in Africa where you can do anything from general community work and sports to teaching in schools; some of the teaching projects so have scope for teaching IT so your geek skills might come in handy, plus you can go for a few weeks so that will fit in with your time scale.
Slashdot Mirror
You might want to check out this company http://www.realgap.com/ they have loads of volunteer programs in Africa where you can do anything from general community work and sports to teaching in schools; some of the teaching projects so have scope for teaching IT so your geek skills might come in handy, plus you can go for a few weeks so that will fit in with your time scale.