“Besplit”:http://besplit.doom9.org/ is a utlity that cuts up an MP3 file intelligently, so it happens on blank spaces. I’ve been using MP3DirectCut to do a similar thing, so another option if you’ve got a big file that needs to be cut.
Another hat tip goes to “Besweet Light”:http://belight.corecodec.org/. This is an easy to understand tool that uses Besweet underneath. It lets you simply transcode MP3 and others applications. You can fix just about anything. Take a 44Khz CD track and use it on a 48KHz DVD track and so forth.