osTicket is PHP-based open-source customer support application that uses MySQL databases. It is one of the options provided by Fantastico De Luxe - really lightweight and easy-to-use. This is a great software for starting your own customer support service.
osTicket may be a simple application but it provides a lot of powerful features that will help both your clients and customer support staff to communicate better and focus on problem solving. Your clients can submit tickets by sending an e-mail or through logging on to your website. There is also an option phone support calls to be added manually by the support staff. osTicket also has auto-response that will provide the customer with ticket number for reference as soon as the request is submitted along with a link for tracking the progress of the issue. Another useful feature is the auto-answer for frequently asked questions. Staff members have an option for internal messaging and notes that will allow them to provide better service. There are also e-mail notifications sent to support staff and clients for any changes and updates on a certain ticket. osTicket keeps history of all submitted tickets so you can review even closed ones for reference.
This splendid application is available in the free scripts installer that comes with each cPanel reseller package and all Dedicated Servers or Virtual Private Servers with cPanel control panel installed. You can set it up for free with just a few clicks.