Dambisa Moyo has given talks and written a book about how aid is harming Africa in a big way. I hightly recommend people check it out. Here's a short version of her talk: http://bigthink.com/ideas/21626
She does a good job of distinguishing between emergency aid (think Katrina or the Indian Ocean Tsunami) which she supports and permanent aid which she says supports corrupt governments and creates a culture of dependency.