here's a program called RipEditBurn, it allows you to edit mp3, wma, or wav files. a 14 day trial is available: http://www.blazeaudio.com/products/mp3editor.html
here's MP3 Wave Editor, it has a 20 use restriction but that shouldn't be a problem. you can download it here: http://www.download.com/MP3-WAV-Editor/300...tml?tag=lst-0-4
at least one of those programs should suit your need so give em a shot :2thumbs: