Since the pioneering studies of GI Taylor in the fifties, models have been used to gain understanding in the propulsion of microorganisms. Modern microfabrication techniques enable us to assemble very small scale devices emulating the motion of cilia. I will review the different strategies used in recent years towards the goal of fabricating micron scale artificial swimmers. In particular I will discuss the relative merits of self-assembly and micromolding. I will describle several sources of propulsive energy but most of the talk will be devoted to magnetically driven systems.