STSoft has released STSideComp, a freeware compressor VST effect for MacOSX.
The STSideComp is a straight forward, full parameterized compressor with a dedicated sidechain input stereo channel. It is designed as a VST effect for MacOSX and is specially created for and tested with Ableton Live.
Developer Oliver Walczak wrote STSideComp to provide a freeware plug-in capable of the typical ducking effect used in modern music styles like (French) House or Techno.
Support for MacOSX 10.5 (Leopard), a GUI, and AU and Windows PC versions (STSideComp is coded in C++) are planned for future updates.
Visit STSoft for more information and a link to download STSideComp.