YTalk is a compatible replacement for the BSD talk(1) program.

The main advantage of YTalk is the ability to communicate with any
arbitrary number of users at once.  It supports both talk protocols
("talk" and "ntalk") and can communicate with several different talk
daemons at the same time.

You may also spawn a command shell in your talk window and let other
users watch.  YTalk supports a basic set of VT100 control codes, as
well as job control (BSD support added in 3.1.3)

WWW: http://www.impul.se/ytalk/