If you're familiar with CLI, you will basically need a static NAT and an ACL to allow the traffic such as:
1.1.1.1 = Inside IP address
2.2.2.2 = Outside IP address
ip nat inside source static tcp 1.1.1.1 80 2.2.2.2 80
access-list 104 permit tcp any host 2.2.2.2 eq 80
interface FastEthernet0/0
ip access-group 104 in
Obviously, the above configuration is not exhaustive, but these are the basics you need to make this work.
I'm fairly certain you can do the same thing using CCA. I believe it's under Configure > Security > NAT. Take a look at the administrator's guide here:
http://www.cisco.com/en/US/docs/net_mgmt/cisco_configuration_assistant/version3_0/administration_guide/cca_30_sbcs_admin_guide.pdf
Hope this helps.
Brandon