Yeah, good point Nick - the thing you need to look at is on the face of the timing case, there are a series of tabs that the timing mark on the harmonic balancer line up with. They are actually numbered too if you look closely (well, a couple are anyway) and 0 is TDC.
Another handy hint, for when the balancer is off, as in mid timing belt change, is the woodruf key (half moon shaped jobbie) for the balancer is at exactly 12 o'clock.
For the cams there are a dot cast in to the front face of the head and a corresponding dot cast into the face of both cam gears, but these are only visible one the timing case is off, and to get the case off you need the balancer off, hence where my hint about the key comes in handy