NoiseTube - a noise measuring app for your smart phone
Provides a fairly accurate measurement of sound, in decibels (db(A)), using your smart phone. Android version available now; iPhone version has been submitted to the iTunes store but is not yet available.
Most people subject themselves to potentially ear damaging loud sound frequently. Several years ago, I had a really bad ear infection that raised havoc with my ears for quite some time. Since then, I am pretty sensitive about the level of sound around me and generally carry and use ear plugs a lot when entering high noise environments. This app can help you learn to recognize damaging high sound situation and take steps to protect your hearing.