Took me an hour to work out. Hope I'm right.
The part of the moon that seems "up" to you is dependent on both where you are on earth (lattitude) and whether the moon is near the horizon or at it's highest.
If you are standing on the equator, the bit of moon that is the top when the moon's rising, will be at its bottom when it's going down.
If you are standing near either of the poles, the same bit will always on top. What is top for the "Southerner" is bottom for the "Northerner"
If you are standing at some lattitude in-between, it is a mix of the two effects. When the moon is rising, both persons (say 52 degrees north and 52 degrees south) will see similar bits "up", as they are both looking East. At the highest, they will see opposite points "up". When it nears the horizon again, the two views will converge again as both are looking West.
Nice links:
Lots of astronomy questions answered
Yahoo group on astro photography