Best Mac OS X Softwares to Cut MP3 Files

Open Source

Audacity is a free opensource audio editor utility which also cross platform.

Commercial

FL Studio is a complete software music production environment or Digital Audio Workstation.

Find apps to do interesting things:

Share files remotely with other people

Send and receive email messages

Backup files online

Combine multiple small images into single image.

Manages or provides interface for easy development environment configuration.

Transfer audio streams from one application to another virtually.