For port forwarding, you'll need something like:
ip nat inside source static tcp 192.168.10.10 3389 3389
ip nat inside source static tcp 192.168.10.11 3389 3388
To allow SMTP traffic from 64.18.0.0/20 to your outside IP address, you need something similar to:
access-list 101 permit tcp 64.18.0.0 0.0.15.255 host eq smtp
interface FastEthernet 0/0
ip access-group in
You would also need a static nat statement such as the above to forward SMTP traffic to an internal address.
Hope this helps.
Brandon
