If David's suggestion of just pressing the 0 button as a part of your message, try press and hold 0 button until it comes up.
Hi Lee, can you tell us what you are trying to do with the Alcatel 768? If you are trying to compose a message, and you need to type the number zero as part of your message, just press the 0 button on the built-in keypad. If you are trying to dial a phone number, the same thing applies. Just press the number zero on the keypad. Let us know if it works!