If you want to forward a port on a public interface on a Cisco device performing NAT firewalling (PIX excluded, I'm sure it's got something special) to a port on a private host, it is necessary to perform destination NAT (inside source NAT):

ip nat inside source static <tcp/udp/etc> <private IP> <private port> <public IP> <public port> extendable

Example:

ip nat inside source static tcp 192.168.1.100 22 66.188.71.74 22 extendable