Dambisa Moyo specifically addresses the bednet issue in her excellent book Dead Aid.

http://www.wsj.com/articles/SB123758895999200083

Even what may appear as a benign intervention on the surface can have damning consequences. Say there is a mosquito-net maker in small-town Africa. Say he employs 10 people who together manufacture 500 nets a week. Typically, these 10 employees support upward of 15 relatives each. A Western government-inspired program generously supplies the affected region with 100,000 free mosquito nets. This promptly puts the mosquito net manufacturer out of business, and now his 10 employees can no longer support their 150 dependents. In a couple of years, most of the donated nets will be torn and useless, but now there is no mosquito net maker to go to. They'll have to get more aid. And African governments once again get to abdicate their responsibilities.