There was a thread at a music production forum I frequent on a specific Audio Unit plugin (Mac only, I think) from Prosoniq that does more than just a band pass, but performs some kind of heuristics to isolate the specific sound and remove it without cutting other sounds that overlap that frequency (such as announcer voices).

I haven't tried it, but it has its own site: http://www.vuvux.com/

It's free; it appears to be a rather clever "vuvuzela only" demo of their full de-mixing package.