Basecamp is a project management tool for tracking website development, design or setting up convergent newsroom remotely. Basecamp tackles project management from an entirely different angle: a focus on communication and collaboration. In a recent customer satisfaction survey, 98% of Basecamp customers surveyed said they would recommend Basecamp to their friends, family, and colleagues. Users can also manage Basecamp projects on mobile phone and iPad. Basecamp mobile is especially made for popular mobile devices like iPhone and Android. No apps are required to use it. The system allows for multiple users to work on the same project, upload files, share the same calendar, seding messages to each other and see what the rest of the team is doing.
(text from http://www.liventerprise.com/tool/basecamp)