I think there is a boatload of opportunity in Africa.
One of the problems in Africa as a market is that there is less than 1% broadband penetration and reliable electricity still only reaches 5%: http://appfrica.net/blog/2008/08/16/the-current-state-of-int...
Apple's products are surely too expensive for the vast majority in Africa, the products can be sold there but it doesn't mean they need offices there.
Google, Yahoo and Facebook need more computers there or to expand more into to mobile there.