IP tables lookup

Anyone know off hand how to look up the prerouting and postrounting rules on iptables?

I've been trying iptables -L NAT and / or iptables -L PREROUTING.
but it keeps telling me no such table. Can someone tell me what I'm doing wrong? (btw yes I know Prerouting isn't actually a table i'm just getting desprate. <g>).

Carl P.