The house should follow electrical code. Black is supposed to be the 115 volt hot lead, white the neutral lead, and green or bare lead is ground. If you have both black and red source wires at the switch, your meter should measure aproximately 230 volts across the red and black wires.
They probably used standard 4-lead romax wire from the switch box to the ceiling rough-in. This provides you with the ability of hooking the fan to one switch and the light to another.
Determine which wires run from the box to the ceiling rough-in and measure the voltage of the source wires at the switch. Then, the rest should be easy.