The disease is found around the equator up to the tropics. The only areas “free” of the plague are mountainous because of the difficulty for malaria-spreading mosquitoes to survive.
The Malaria Atlas Project has detailed maps both static, animated, and in KML format along with the supporting data.
A major way the stop infections is to have mosquitoes nets cover one-self as one sleeps. The infected mosquitoes tend to come out at dusk and night. For those interested in helping the distribution of nets check out Against Malaria for more information. The charity even has a map page of where the nets are going!