Very recently (The past hour an a half) I walked my mother through (via the phone) adding her new computer’s MAC address to the Wireless MAC Filter on her Linksys router.  After a while, I thought it would be easiest if I could see the same screens she was.  After a few minutes of research I found out that Cisco makes accessible all major versions of their routers and modem configuration interfaces online.

They are organized by model number and then firmware version.

http://ui.linksys.com/files/