If you're into a bit of coding, the file format specification for MP3 frame headers is here. You could create a script or something to do it. The code isn't that tough, my GapKiller program just has a little routine to scan forward through a file finding each frame header, counting as it goes, and copying those frames to another file. I just change the copying process to go to a new file at a predetermined point (by number of frames). Since each frame in a 16-bit 44khz stereo file is always .02612 seconds long regardless of bitrate, I can pretty accurately determine the time index of the split.