ics.el is a comint based Emacs major mode for handling the text portion of communications with internet chess servers such as FICS and ICC. It is written in Emacs-Lisp and works best in conjunction with a graphical interface such as Xboard. It handles colour highlighting and "buttonisation" (making certain portions of text active so that, for example, you can challenge opponents with a single mouse click) as well as command recall and editing and automation of commands based on regexps seen in the ICS output, all highly customisable using Emacs lisp.
As a long time SCID user I can't praise this program enough. It's full-featured, easy to use, well documented, fast and, of course, it runs on my platform of choice (Linux), which the commercial vendors seem uninclined to support. (SCID also runs on windows, for those so inclined.)
In any case, SCID has just about all the features of the commercial offerings and an author who listens to and implements feature suggestions all the time.
Hats off to Shane for an excellent piece of work.