Try Friends Reunited, thats the most obvious answer to your question. Although you need to pay, in order to send messages to people. Its �7.50 for a year.
Or, trying using something called 'Hi5.' Its a friendship/social network. You can look people up by typing in their names. Sometimes the profiles have photos and the profiles may give information about themselves. With Hi5, you dont need to pay to send messages; its free. But you do need to register with the sevice.