Transmission - A fast, free, and multi-platform BitTorrent client.
Transmission establishes initial preferences so that things "just work", while advanced features such as watch directories, bad peer blocking, and the Web interface can all be configured in just a few clicks. It supports file selection, full encryption, file selection and a Web-based interface.
Its code can be freely downloaded online under the GNU Public License v2 and the MIT License. Anyone interested in contributing code, documentation or translations to the development team is welcome.
Note: Now requires OS X 10.10 or later