This paper explores the adoption and application of Web 2.0 tools in delivering library services in selected libraries in Tanzania. The paper investigates the ways in which librarians are adopting the tools to enhance services. The study examines Web 2.0 tools used by libraries in delivering their services, factors influencing the use of Web2.0 tools, challenges and prospects in their usage. The findings reveal that librarians in Tanzania have started using various Web 2.0 tools in varying degrees and the most common tool is Facebook. The findings also reveal that most librarians are motivated to use these tools because they are free and open source and relatively easy to apply. Sharing resources, communication and promotion of services were the main reasons why this tools are used. Challenges include unreliable power and internet access. Advantades included, increase in resources awareness, better communication and interest in library usage. Recommendations suggest that institutions should develop policies that adopt the use of emerging technologies and alternatives to reliable power sources such as solar and generators.