Recently, charter schools have gained popularity with parents, students, and others as alternatives to public schools, but what are charter schools and what effects are they having? This Spanish-language Digest defines charter schools and clarifies some of the administrative and legal details surrounding such schools. The Digest also lays out some of the potential benefits of and problems with charter schools, distinguishing commentary on charter schools from research on them, which is sparse. Proponents of charter schools say that charter schools increase parents' school choice and compel public schools to make improvements they otherwise might not make. Opponents argue that charter schools divert public monies that should be used to improve urban and rural public schools in low-income communities. Opponents also say that many charter schools are financially unstable. The Digest also highlights some research findings concerning issues such as academic achievement, parent satisfaction, and provisions for special education. (Contains 18 references.) (HTH)