Ubuntu will pick up your network cards individually and you should have a little network icon on the bottom or top of your screen which you can open up to view your network connections and open them up to make changes. If its not there you can also get to it through administration > Network
It will show each Network card as a separate connection and you can configure each one individually
Network interfaces configuration is defined in the /etc/network/interfaces file, so, you could manually modify this file with the appropriate settings. You can read the man page or search the web for details about this file.
Here is a simple example, where one card is configured to use DHCP, and the other is configured to use a static IP address:
iface <b>eth0</b> inet dhcp
iface <b>eth1</b> inet static