Awesome!

Works great, would be worth it even without the filters and recording capability. It would be nice to have a feature to stop sounds over a given threshold from reaching your ears (like a brick wall limiter of some sort). But for $2 this is a 6 * app. Yet another tool to add to the iPhones amazing array of them...

darkcrayon about SpyApps - Listen Up: Advanced Noise Filtering Voice Recorder and Amplifier