The purpose of this paper is to illustrate the importance of using open source technologies and common standards for interoperability when implementing eHealth systems and illustrate this through case studies, where possible. The sources used to inform this paper draw from the implementation and evaluation of the eHealth Program in the context of the Millennium Villages Project (MVP). As the eHealth Team was tasked to deploy an eHealth architecture, the Millennium Villages Global-Network (MVG-Net), across all fourteen of the MVP sites in Sub-Saharan Africa, the team recognized the need for standards and uniformity but also realized that context would be an important factor. Therefore, the team decided to utilize open source solutions. The MVP implementation of MVG-Net provides a model for those looking to implement informatics solutions across disciplines and countries. Furthermore, there are valuable lessons learned that the eHealth community can benefit from. By sharing lessons learned and developing an accessible, open-source eHealth platform, we believe that we can more efficiently and rapidly achieve the health-related and collaborative Millennium Development Goals (MDGs).