Windows XP Network Bridge
In Windows XP, a Network Bridge is a feature that is used to combine two or more local area networks (such as wired and wireless) into one logical network. Computers on each network can communicate with computers on all of the other networks, sharing files, printers and even an Internet connection.
To create a bridge between two or more network connections, open the Network Connections folder. Hold down the Ctrl key while clicking the desired connections, then right click one of them and select Bridge Connections. The Network Bridge will appear in the list of network connections, along with the connections that are included in the bridge.
The Network Bridge takes on most of the attributes of a normal network connection. To configure it, right click the Network Bridge and select Properties. You can add or remove connections from the bridge, enable protocols and clients, assign an IP address, create a connection icon in the notification area and other options. When a network connection is added to the Network Bridge, it loses its individual attributes. It no longer has an IP address, clients, protocols, and so on.
See also "XP ICS - Network Bridge" on PracticallyNetworked.com.