See attached image for what my Firefox 3.6.13 and Internet Explorer 8.0.6001.18702 proxy config pages look like.
FF: Tools -> Options -> Advanced -> Network -> Settings IE: Tools -> Internet Options -> Connections -> LAN Settings
Make sure you're using ONLY OpenDNS servers in your router's DNS settings. It appears that CenturyLink's DNS servers are messed up. Just google "centurylink dns" to and read some of the links. Afer changing your DNS settings, you might want to run ipconfig /flushdns from a command prompt too.