Those addresses are usually assigned to the router. IIRC, Linksys uses 192.168.1.1 by default. Once you gain access to the router's administration screen at that address, just locate the wireless security section where you'll be able to change your password.
TIP: If you're using Windows, you can go to Start->Run, enter "cmd" (no quotes) in the little box that pops up, hit enter, and at the command line, enter "ipconfig" (no quotes). It will dump several IP addresses. The one marked "Default Gateway" is the IP address of the router.