Neat idea with decent delivery. I'd expect to see some company ID from the ones that are in your listing. Maybe there's an option to bring logos to your site, eventually some event pictures and the most important part: Consumer Rating. After all, i'd like to know how others experienced the entertainer's services.
User accounts to save their favorite and most used entertainers and for user feedback/ratings, would help as well and give you immediate customer buy-in.
The visual delivery is a bit too ... well,..blue

Break the listing up by using at least different shades. Implement Google maps so people can either find the venue or the office of the entertainer.
Also, revisit your logo: entertainment, especially on a professional level is more than clowns or karaoke, which i assume is represented by the stereo.
The credibility depends on the content, the recognizability on your design and foremost your logo.
Other than that, response time, loading times and general intuitive handling of the site - A+