Current version (as of April 2012) is 0.6.2. Now also hosted at GitHub: https://github.com/Eule/StreamRipStar/wiki .
To install StreamRipStar, you'll need to:
1. Install Xcode https://developer.apple.com/xcode/
2. Install and update MacPorts http://www.macports.org/
3. sudo port install streamripper
4. Run StreamRipStar0.6.2.jar. Set streamripper path to /opt/local/bin/streamripper in the Preferences.