Internet Relay Jabber (or IRJ) is a Jabber client for IRC. It's useful if you like IRC, but your friends use another IM service. It is written in Perl and uses Net::Jabber and Net::IRC. (This project is no longer under active development)
This is an Instant Messenger client and server written fully in CGI with Perl. Users can register their nickname, and chat when anyone comes online. Also you can see they webcam.