192.168.1.1

To initially set up a router you have to connect by ethernet cable and run the install cd. The router address that is used to access the routers internal settings is either on the router or in the user manual. Most of the time it's 192.168.1.1 but there are other addresses that are uased and 192.168.0.1 has also been used by some brands.
The user name and password will also come in the user manual and on all routers each brand will use a default user name and password and once connected that can be changed.