Yeah, I've taken Malaria Pills already. We're staying for 2 weeks, in Lilongwe and Blantyre. The flight is like 24 hours in total. From Shanghai to Hong Kong, then Hong Kong to Johannesburg, then Johannesburg to Blantyre.
I've been to the one of the Joburg airport terminals. It's really beautiful, you should take some pictures while you are there.
Also, I've been to a place like Malawi and I recommend that you get a fannypack (or those small bags you could clip around your waist.) It's awfully dangerous in places like that, especially if you are not black.