Different router models have different default LAN IP addresses (the address that any computers on the local network use to connect to the router). For you, that address is http://192.168.1.1. I've got Verizon FIOS, and that's my LAN IP address as well. Kevin's suggestion of http://192.168.100.1 applies to some cable modems. Since slolerner made reference to "the cable company," that may well be the correct address.
Note that you can easily ascertain your own LAN IP address via System Preferences -> Network -> Ethernet. Since these panes seem to be redesigned with every OS X upgrade, I won't try to be more specific than that, but somewhere you should see IP Address, Subnet Mask, Router, and DNS Server. ("IP Address" in this case refers to your Mac's LAN address; Router is the one you're looking for).
