Agora is a Web-based, threaded discussion tool, similar to Usenet newsgroups. Agora remembers each user's preferences, and allows threaded, unread-only browsing. It offers the ability to manage several different groups, with different themes, forums, and administrators for each group. Agora offers a basic Web-based ICQ client, as well as a Web-based notes system.
GNUSTEP Live CD contains a lot of software for GNUstep, a free implementation of the OPENSTEP framework (which is also directly used in Mac OS X as Cocoa). It includes excellent applications for RAD (GORM and ProjectCenter). The CD is available for i486, AMD64, Apple Mac PowerPC, and Sun UltraSPARC computers.
Gnus is an extremely powerful, configurable news and mail reader written in Emacs LISP for GNU Emacs and XEmacs. It provides threading, sorting, and article scoring; can retrieve messages via NNTP, local news or mail spool files, IMAP, POP, and other methods; and has features that make it efficient for reading news over low-speed network connections.
Hitchhiker's Guide to the Internet is a German introduction to the technical aspects of the Internet. This book explains both the low-level protocols IP, ICMP, TCP, and UDP and the high-level protocols SMTP, POP3, IMAP4, NNTP, HTTP, Gopher, FTP, IRC, DICT, Finger, Daytime, DNS, and Whois.