First of all I'm a Mac guy, secondly not really into audio applications so I'm looking for something simple - perhaps a plugin for a Final Cut Pro or Peak? I can use Virtual PC too so if there is an app for that doesn't take up entire HD and eats RAM like crazy I could use that too.
Sound Soap or Sound Soap Pro will do this in Peak. (http://www.bias-inc.com/products/soundsoap/) The interface is impossible in FCP4.5. However, if you can wait, the new Soundtrack Pro will have this functionality built in.