Shortening a Piece of music to make a "clip"

OK so I have managed to extract tracks from my new CD on to MP3 format using Windows Media Player. First step achieved.

My next worry is this.

How can I reduce these clips all down to exacty 60 seconds?

This is preferred for copyright purposes.

Radio Stations could still get a good taste of the music from the new CD and decide whether they want a copy for Airplay, but without me having to 'give away' copyrighted tracks to the whole world for free.