1) If you didn't play the Australian lottery, you cannot win it, despite what that e-mail says.
2) If you get an e-mail from a friend who needs cash because he got mugged while overseas, pick up the phone and call them. I guarantee they never left town. This is a popular scam.
3) That monetary award from Africa requires shipping costs, or paying any up front fees is bogus.
4) That prize that you won that requires shipping costs to be prepaid is a scam.
5) Those offers to get paid to receive and then re-ship goods generally involve receiving purchases from stolen credit cards and shipping them off. Guess who gets caught holding the bag with the stolen goods.