I have released an audio comparison utility for win32 called ABCHR (stands for ABC/Hidden Reference) under LGPL.
http://ff123.net/abchr/abchr.html
The utility allows blind rating of multiple audio files. Each time a listener rates a sample, he is forced to choose between the sample and the reference (he doesn't know which is which, hence the reference is "hidden").
The utility should facilitate statistical analysis of group listening tests by providing a method for post-screening of listener responses. If a listener just guesses and repeatedly rates the reference less than 5.0, then his results are suspect and may be discarded.
The utility in it's initial form is ready to be used in group tests. However, there are some future enhancements which would be very useful, including the ability to seek within a file, and the ability to "hot" switch between samples without starting at the beginning every time.
ff123