Server side scripting and database

I want to do the following thing on my webpage. In a text box which I provide to the user, when the user enters one letter inside the text box, I want to retrieve all the names starting from that letter from my database and display all the names and the corresponding details from the database in a creative way. How can I achieve this? Can I do this using PHP? Is so, how? if not which tool from the web will help me do this? Please note that I want all the details to be specified on the webpage as soon as the user enters the letter in the text box. I dont want the user to click a button and then do the above. It should be instantaneous, as soon as he enters the letters he gets the relevant information.