CocoaNote is a simple, easy-to-use WYSIWYM music notation editor for OS X. Its goal is to be useful for composing and arranging music, while import/exporting to other file formats for compatibility and in order to produce pretty printouts.
OpenTimeLine is a project to provide to the community a framework and a new kind of Music sequencer dedicated to graphical scores. It use the fudi protocol to sequence events for Pure Data.
This software allows a user to tag mp3 files, on any plateform. It has a very simple interface. It can retrive tag information over Amazon database, from file names, or from user entry.
Replacement for the Java Media Framework (JMF), allowing you to transport not only audio and video. In extention a modular software synthesizer designer/sequencer sharing local hardware over the internet.