We have worked on audio analytics in the past for things such as outdoor sound detection and vehicle identification. We are currently focusing on speech-based analytics such as language ID and affect recognition. The statistical methodologies we are using for speech are easily extended to such domains. We hope that by puuting out these initial speech services we will get feedback from the community about related problems and welcome your suggestions.

You might want to check out Echonest's API - http://developer.echonest.com/