Formal languages and automata theory (FL&AT) are central subjects in the CS curricula which are usually diffcult both to teach and to learn. This situation has motivated the development of a number of computer simulators as educational tools which allow the student to implement and `bring to life' many topics which traditionally were studied and analyzed mathematically rather than algorithmically. This paper discusses the main features of several educational software tools currently available for teaching FL&AT. Advantages and weaknesses of different tools are analyzed and contrasted. Based in our experience, some rationales and practical considerations for the development of this kind of educational tools are proposed.Eje: Tecnología aplicada en EducaciónRed de Universidades con Carreras en Informática (RedUNCI)