I have 2000 S3, on that you look down by the left hand side of the battery, there is a small black plastic/rubber cap. take that off and the bleed nipple is just under that. it is just next to the gear change mechanism, towards the front.
As Ross has just said, look on top of the gearbox between the battery and the head, you'll see the hydraulic pipe (looks like a brake line) come in from the right. Close to this is a bleed nipple, usually with a rubber cap on it.