According to http://wiki.answers.com/Q/Which_way_does_water_go_down_drain_in_Australia, the water goes down in any direction depending on how the water was spinning at first. If the faucet which you use to fill a container is ever so slightly inclined to the left or to the right, this will give the water a spin that will last for at least a day. Coriolis effects - effects due to the rotation of the Earth - are usually quite secondary.
 
Today, my group and I went for a little trip to the lady's room to watch in what direction does the water drains down the sink. I put my hands above the drainer and let the water fill up the sink, after I removed my hands from above the drainer, we came to a conclusion that the water was spinning counter clock wise.