SIM (Simple Instant Messenger) is a plugin-based instant messenger with
support for various protocols.
(QT is needed, can be build for KDE).

All protocols support richtext-messages, file transfer, typing notification,
server-side contact list (with postponed synchronization - you can change
contact list in offline mode and after log on all changes will be
synchronized with server), new account registration and various searches.
You can use several accounts for each protocol.
 
Supported protocols:
    * Oscar - ICQ and AIM support
    * Jabber
    * MSN

WWW: http://sim-icq.sourceforge.net/