Since Soundtrack Pro is part of the Final Cut Studio you will want to use a program that is designed to remove programs that are a part of this package, or a program that is simply designed to uninstall software. FCS Remover is an application that allows you to remove everything from your computer that is a part of this package or an associated program that is part of a related package, such as Final Cut Express and Final Cut Server. When it is removing the software, it will leave the essential files the software has created or modified, such as your projects, rendered files and captured footage.
The default for FCS Remover is going to be to delete everything that it is set for, which is Final Cut Pro/Express, Motion, Soundtrack Pro, DVD Studio Pro, Color, Live Type, Compressor, Cinema Tools, Qmaster, Final Cut Server and Shared Files. You will want to check just Soundtrack Pro and make sure all others are unchecked before you hit the Remove Selected button. In the Preset option at the top, you should choose Maximum Compatibility if you do not intend to reinstall the program you are deleting, and select All if think you'll reinstall the program in the future. Once you do choose to remove Soundtrack Pro you will be asked to confirm your decision, and it will then go through the removal process.