IM (Instant Messaging) with Pidgin
Pidgin is an instant messaging program for Windows, Linux, BSD, and other
Unixes. You can talk to your friends using AIM, ICQ, Jabber/XMPP, MSN
Messenger, Yahoo!, Bonjour, Gadu-Gadu, IRC, Novell Google Talk, GroupWise Messenger,QQ,Lotus Sametime, SILC, SIMPLE, MySpaceIM, and Zephyr. The client you could download here. No administration rights is needed to install the client!