* operator in python tutorial

[ben]

Hello,

I am following through the python tutorial which gets to a line that
uses the * operator with zip(). I searched and searched but could find
no information on the operator or how to use it in general. The
example from the tut is as follows:
>>> x = [1, 2, 3]
>>> y = [4, 5, 6]
>>> zipped = zip(x, y)
>>> zipped
[(1, 4), (2, 5), (3, 6)]
>>> x2, y2 = zip(*zipped)
>>> x == list(x2) and y == list(y2)
True

How would i apply the * operator in general?
Thanks.