Notifyme is a gpl'ed unix (tested under linux, freebsd and openbsd) console utility that stays in a background (it isn't a daemon but it doesn't block terminal) and prints a message if a specified login and/or logout occurs. in a resource file ($home/notify.rc by default) you can specify (extended regular expressions are allowed) usernames, hostnames and terminals that should be monitored, optional messages that will be displayed and other options (beep, report logouts etc.) see notifyrc.sample for examples. it should be self explanatory.