Microsoft Solutions Framework (MSF) is a set of principles, models, disciplines, concepts, and guidelines for delivering IT solutions. MSF allows developers to choose between methodologies like Waterfall and Agile. It aims to help developers successfully deliver solutions by working fast, reducing risks, and ensuring high quality results. MSF includes a metamodel with principles, team models, and cycles/iterations. It also has a process model using short development cycles and iterations for continuous learning and refinement.