
The Sound Guy, Inc. has released Backwards Machine, a cross-platform plug-in that reverses continuous audio in real-time. 
Backwards Machine includes three effects : 
 - Reverse Playback — Reverses and overlaps snippets of the incoming audio, to produce an ongoing backwards effect
 - Forward Backwards — Smoothly cross-fades between forward and backward versions of the incoming audio
 - Reverse Repeat — Plays snippets of the input audio backwards, twice; the second time, a slight vibrato is added
Backwards Machine supports VST and Audio Unit formats for Macintosh OS X (Universal for PPC and Intel) and is available for $35.00.