There is also a djing plug-in for Winamp. I've never used it myself, but my friend has and it can match tempos etc. Maybe if you can use that in conjunction with the wave writer or soundforge...

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When you dance, the DJ takes you on a journey, but he or she is usually not the focus of your experience at a club or festival or wherever you hear the music. Dancing is. Music is.

The plugin for winamp is called DSP pitch. It is good and i use it personally but it makes one hell of a horrible ringing / watery effect but this is the same as using programs like AtomixMP3, BPM Studio, PCDJ etc...

I reccomend programs like cool edit pro and soundforge but as you say it dont work with trials but you could always do the naughty thing which im not gonna say because ill probablies get my ass kiked

tezz