I need a person who can do MySQL, PHP, Javascript

I need person who would able to do the data base with PHP and inside will be javascript on very similar as tweeter or chatroom like basis. I can not reveal the core of the business for security reason, however, I will pay not bad money and on top of that, the person I will stick with may have a long term contract with very good salary. However, I do not want to pay until I will see the core of the business!!! The design- appearance, is not as important as this will be different topic for different person from particular field. If You have any question i will be very happy to discuss!