The development, integration, and distribution of the information and spatial data infrastructure necessary to support the vision and goals of a digital Earth will occur in a distributed fashion, in very diverse technological, institutional, socio-cultural, and economic contexts around the world. Free and Open Source Software for Geospatial Applications (FOSS4G) offers mature, capable and reliable software to contribute to the creation of this infrastructure. A recent paper presents a selected set of some of the most mature and reliable FOSS4G solutions that can be used to develop the functionality for a digital earth. It includes examples of large-scale, sophisticated, mission-critical applications of each software to illustrate their potential in support of a digital Earth. Information and resources are offered to help users select the best FOSS4G solutions for their particular contexts and system development needs.