Pidgin is a freeware that has come to be known for its usefulness. It is basically a multi-protocol instant messaging client and now it is portable. Pidgin is compatible with IM (Oscar and TOC protocols), Yahoo, ICQ, MSN Messenger, Gadu-Gadu, IRC, Jabber and Zephyr networks.
What it can do for your messenger experience is immense. You can log on the multiple IM networks simultaneously. So, you can chat with your friends on MSN while you another on Yahoo. The interface is such that you can see multiple conversations in the same window. Pidgin enables you to setup the protocol, login and password for each account. Apart from all of this, it contains various ways through which you can make your messenger experience more fun like statuses, notifications with sounds and so on.