The document discusses how project-based learning (PBL) can leverage Web 2.0 tools to develop 21st century skills. It provides an overview of the benefits of PBL, examples of challenges and exemplar projects, as well as recommendations for specific Web 2.0 tools that can be used for project organization, collaboration, research, and publishing. These include Google Docs, Wikispaces, Voicethread, and Glogster for collaboration, Diigo for annotation and discussion, and Google Calendar for task scheduling.