PolderbitS Sound Recorder and Editor is created especially to help users digitize cassette tapes and vinyl recordings.
— Is there a version of Polderbits that will run on iMac?
No, this application is not available for iMac because it's not available anymore. I have checked all the possible websites, but didn't find anything regarding the Mac OS compatibility....
However, if you still have the package, you can use Wine Bottler to install the application on a Mac OS X environment. Wine Bottler allows you to run Windows apps on Mac OS X operating system.
Download Wine Bottler: http://winebottler.kronenberg.org/