Radium Audio has released the Radium Compressor as a Linux VST plug-in.
Radium Compressor is a compressor/expander with a unique user interface. It visualizes the sound compression in an effort to help the user find good compressor settings. It is also available for Windows as a VST effect plug-in, and for Mac OS X as both a VST and an AU plug-in.
Price: €25.