http://www.blazeaudio.com/products/wavecreator.html is a cheap wav creator and editor that allows for reverse play. There is also a VB script that you could use. If you want the script let me know and I will post a link. I imagine many of the big music programs (Acoustica, Fruity Loops, etc) probably provide a means of playing in reverse as well.
__________________ \"The surest way to corrupt a youth is to instruct him to hold in higher esteem those who think alike than those who think differently.\" Friedrich Nietzsche
backwards playing software 
Linear Mode
