Marginalized populations lack access to digital technology yet aspire to participate meaningfully in the digital public sphere. Mobile Voices offers an open-source multi-media platform optimized for low-cost mobile phones that lets users create, share, and reflect on stories about their lives and communities. An academic-community partnership, the project brings together immigrant day laborers, scholars, software developers, and community organizers for participatory design, curriculum development, evaluation and research around this emerging media tool and its social impact.