<<<Does anyone know how to get the client pc to know it is shared?>>>
The Client PC isn't "shared" as such - it gets its internet access over the LAN from the Host PC's shared connection.
When ICS was enabled on the internet connection in the "host", its Local Area Connection will have been given the IP address 192.168.0.1 subnet 255.255.255.0 and the "client" should be set to get its IP address automatically, which it does by DHCP from the "host".
If you open a Command Prompt window in the client, type IPCONFIG /ALL and press Enter, you should see the IP address that has been allocated to it and which should be in the same 192.168.0.xxx range. If you are running firewall software, the IP addresses of the networked PCs need to be entered in its "trusted" area. Also, if running Zone Alarm in the "Host" PC, the Internet Zone Security setting must be reduced from High to Medium or ICS traffic will be blocked.