wifi not connected

I tried the Ubuntu 7.10 live CD on my laptop and was able to configure my wireless connection with WPA and then connect to the internet - no problem. After installing Ubuntu I found that the Network Settings were still configured correctly however I was unable to establish a connection. I re-loaded the live CD again and found I could connect once more. Clicking on the network connection icon shows all the local wireless connections available on the live CD but only gives me the option of "Manual configeration" on the installed system. Is "Network Manager" not installed?