I watched a bit of "Live 8."
It was clear that at the heart of it was a genuine concern for the poor and the suffering in Africa, even if wrapped in many layers of media hype. Aside from raising funds, though, there was a political message, calling for increased aid and debt forgiveness for African countries, and a lowering of trade barriers.
The latter is the easy part--freer trade in African commodities will surely not make a dent in our economy, but to small, weak economies that rely on these items for much of their income, it might make some difference. (I haven't looked it up, but my bet is that our tariffs on all but politically privileged commodities (think sugar) are nonexistent or low.
Aid? If government to government, I doubt it will make much difference. Africa suffers from at least three treatable maladies--disease (AIDS, malaria), corrupt governments, and socialist and dirigiste policies that hold back the kind of economic growth we've seen in East and South Asia and parts of Latin America.
Disease, in turn, is due in part to governmental inefficiency and in the case of AIDS, to a gender sexual culture that accepts male infidelity and prostitution. Greater resources for AIDS treatment, and the fight against malaria (including limited use of DDT) may make some difference here.
But at the core of the African problem is the corruption and tyranny of its governments. I did not hear about Robert Mugabe of Zimbabwe, who has initiated a horrid genocide of much of his population, has destroyed agriculture, and suppresses all opposition, or any other of the swinish, incompetent and corrupt régimes that dominate the continent.
Unless those issues are addressed, aid, unless it goes to honest NGO's, is not going to accomplish much.
These ideas are hardly original with me--but too subtle for a passel of rockers and movie stars.
UPDATE: There is at least one success story on the continent, as discussed here--the landlocked country of Botswana, relatively free from corruption, and protective of property rights. It has the highest growth rate in the world, so they say.