In this work a novel approach to acoustic source localization in reverberant environments is introduced. The proposed method effectively employs particle filtering (PF) and particle swarm optimization (PSO) in an integrated framework. Source localization is viewed as a global minimization problem where the solution is searched by properly exploiting competition and cooperation among the individuals of a population. Experiments on simulated data show that the proposed strategy is fast and robust with respect to the presence of reverberation.