A book by Kennedy, Eberhart and Shi.
This book is intended for researchers, senior-undergraduate and graduate students with a social science, cognitive science, engineering, or computer science background, and those with a keen interest in this quickly evolving "inter-discipline." It is also written for what is referred to in the business as the "intelligent layperson." You shouldn't need a Ph.D. to read this book; a driving curiosity and interest in the current state of science should be enough. The sections on application of the swarm algorithm principles will be especially helpful to those researchers and engineers who are concerned with getting something that works. It is helpful to understand the basic concepts of classical (two-valued) logic and elementary statistics. Familiarity with personal computers is also helpful, but not required. We will occasionally wade into some mathematical equations, but only an elementary knowledge of mathematics should be necessary for understanding the concepts discussed here.
Sample source codes are available for download
Particle Swarm Central
Open directory project - particle swarm section