I used to have an excellent piece of software called “Cool Edit Pro” which was sound editing software by a company called Syntrillium Software. It was considered to be the best, and was used by the best, in the business. In 2003 it was bought by Adobe and became known as Adobe Audition. However, it was limited to Windows only.
Only this month has a beta version been released for the Mac and you can download it for free at Adobe Labs. Indeed, Adobe Labs is a great place to go to try out new and emerging software ideas. It can potentially keep you ahead of the game and maybe save you a small fortune using developing software rather than buying a more polished product.