I'm pretty sure that http://gabuku.com/scope/ArduinoScope-source.zip is the source that produces http://gabuku.com/scope/Macduinoscope.app.zip .
I haven't compiled it to check though, as I don't use a Mac, but I used it as a guide to write the serial-handling parts of my app.
For completeness, http://gabuku.com/scope/arduinoScope.pde is the Arduino sketch sourcecode.
pix.