Task Manager Keyboard Shortcut

ALT + CTRL + DEL will open task manager directly if your system is configured to display Login Welcome Screen

Other shortcut :
ALT + CTRL + ESC

Pidgin

Pidgin is an Instant Messaging client which supports many IM networks such as AIM, IRC, MSN, Yahoo, Google Talk and others.

Download Link


Trillian & Miranda are also good multi platform instant messenger clients.