For information on malaria there are numerous websites, in addition to some good articles in Wikipedia.
Start with the following sites:
www.rbm.who.int (Roll Back Malaria)
www.tulane.edu/~wiser/malaria/cmb.html (Tulane University)
www.malariavaccines.org (Malaria Vaccine Initiative)
View this superbly graphic simulation of invasion by Plasmodium, from mosquito to blood: