Arduino which library for led 4x20
0x63 is the correct address - the module is at 0xC6 which is the 8-bit equivalent of 0x63 (0x63 shifted left once for the read/write bit to be added).

The LCD03 uses its own custom I2C protocol, not compatible with the "normal" I2C LCD library. Instead you have to use their own special commands.

The commands are detailed here: http://www.robot-electronics.co.uk/htm/Lcd03tech.htm

There may be a library available that wraps those commands, I don't know, but you can just use the Wire library to send the commands you need to send.