The Fall of Man occurs when a snake gets Eve to eat from the forbidden fruit. This is Genesis 3:1:
And so humanity's troubles begin. Problem: snakes don't normally talk. But the standard Christian understanding is that the serpent is being controlled by Satan; a view echoed in other places, e.g. Revelation 12:9.
If this is correct then there's little difficulty. But the idea of the serpent as Satan is actually quite a hard thing to read into the text. The verse given above (3:1) suggests the snake is just another beast of the field. Also, when God distributes punishments for these events, he seems to punish snakes rather than Satan. This is Genesis 3:14-15:
One can dissolve these problems by suggesting that the whole account is intended as myth, with the Fall representing something that happens in each of us, rather than a historical event. This likely won't appeal to many inerrantists, so another suggestion is that verses 14-15 still refer to Satan; who is indeed cursed. One interpretation of the enmity between the serpent and the offspring of woman is that this ultimately refers to the triumph of Jesus son of Mary, over Satan - a reading you'll find in the ESV Study Bible, but which is hardly obvious from the text itself.
Updated: 2009-12-06