Coding and Cryptography - http://www.dpmms.cam.ac.uk/~twk/ Lecture notes (DVI,PS,PDF,LaTeX) by Tom Koerner for a course at the University of Cambridge.
A Mathematical Theory of Communication - http://cm.bell-labs.com/cm/ms/what/shannonday/paper.html Claude Shannon's seminal paper, made available by Bell Labs in PostScript and PDF.
Werkgemeenschap voor Informatie en Communicatietheorie - http://www.w-i-c.org/ To coordinate and stimulate the work of professionals in the field of information and communication theory in the Benelux region. Member information, events, publications and links.
IEEE Communications Society Communication Theory Technical Committee - http://www.comsoc.org/socstr/org/operation/techcom/theory.html The Communication Theory Technical Committee of the IEEE Communications Society promotes information exchange and dissemination in the broad area of Communication Theory, with emphasis on applications to practical systems.