Google Talk is text and voice instant messenger, that enables you to communicate with your friends via voice (microphone required) or traditional text messages.

Pidgin is a chat program which lets you log in to accounts on multiple chat networks simultaneously. This means that you can be chatting with friends on MSN, talking to a friend on Google Talk ..

With Skype’s free software – by the way, it works seamlessly with your internet connection – you can chat away with free Skype-to-Skype calls and never worry about cost, time or distance.

Windows Live Messenger is the next generation of MSN Messenger. It supports video chats, phone-to-phone, phone-to-PC calls and conventional text chats with full support for emoticons, font formatting and more. Windows Live Messenger integrates support for Yahoo! ..

Yahoo!Messenger is an instant messenger that lets you stay in touch with other Yahoo! users. It includes features like PC-to-Mobile conversations, emoticons, web cam support, Yahoo! email integration ..