GnomeICU is one of the most popular UN*X-based ICQ programs in the world.
Internet chatting has quickly become one of the most popular uses of the
Internet - second only to Email.  Instant messaging allows users to
communicate in real time with friends, family members, and coworkers in
an efficient, unobtrusive manner.  GnomeICU has support for all of the
following ICQ features:

* Server-side list storage.
* Basic messaging.
* File transfer (temporarily broken due to protocol change).
* Contact history.
* Visible/Invisible/Ignore lists.
* Ability to interface ICU from the command line.
* Icon themes.
* Many more.