I read an article similar to this one awhile back that claimed that DDT was unfairly maligned and could save millions of lives by killing mosquitoes. Then I read this article refuting many of the more convincing points--saying basically that DDT isn't the magic bullet some claim it is. Which to believe? I don't know.
UPDATE 22 May 2007: I'm still no expert on DDT, but the topic seems to be growing in popularity again as we approach the 100th birthday of Rachel Carson, author of Silent Spring. Opinion Journal has a piece that looks disapprovingly on the unintended consequences of banning DDT. We now use more, less-potent pesticides with less effect.