There is a Unix utility called linksysmon that talks with these boxes via SNMP. There is a Linksysmon project site.
Linksysmon is a tool for monitoring Linksys BEFSR41 and BEFSR11 firewalls under Linux and other Unix-like operating systems. It accepts log messages from the Linksys, and logs the messages to /var/log/linksys.log. It handles the standard activity logs, as well as the "secret" extended logging, and can handle logs from multiple firewalls. When using extended logging, it can detect external IP address changes (if you are using either DHCP or PPPOE) and can call an external program to process the change.
Link-n-Log is a similar tool that includes a GUI and logs to an SQL database. Details at the Link-n-Log project page.