GNet is a network library. It is object-oriented, written in C, and built upon GLib. It is intended to be easy to use and port. It supports abstract Internet addresses, TCP, UDP, IP Multicast, IPv6, asynchronous DNS lookups, SHA, MD5, Base64, URIs, and SOCKS. It comes with documentation and examples.
gnokii is a multisystem tool suite for mobile phones. It provides a library to communicate with a phone hiding the communication protocol. The library handles SMS, phonebook, calendar, phone calls, and other mobile phone capabilities. It supports Nokia-FBUS mobiles, AT-capable phones (most of the mobiles), as well as Symbian-based phones.
Gnome-o-phone is an internet telephone. In other words, if you and your friend have computers with sound cards and network connections, you can use gphone to talk to each other and save on phone bills. Gphone uses GSM compression, so the data rate should be low enough to work over a reasonable modem connection. Gphone supports full duplex if your sound card does.
Pipo-BBS allows you to install a BBS server and clients. You can chat via a nice interface with an unlimited number of people (as with IRC). This software is in a pre-release state; it is still very alpha, and can be difficult to even compile. It works under linux, MkLinux, SGI, HP-UX, and Solaris. The only interface for this BBS is telnet for the moment; an interface using GTK has been started. It has been translated into French, English, Spanish and German.
gpsd is a daemon that listens to a GPS or Loran receiver and translates the positional data into a simplified format that can be more easily used by other programs, like chart plotters. The package comes with a sample client that plots the location of the currently visible GPS satellites (if available) and a speedometer. It can also use DGPS/ip.
Greenstone is a complete digital library creation, management, and distribution package for Unix, Windows, and Mac OS X. Users create collections by gathering a set of input documents, specifying a configuration file, and running the build script. It provides full-text and fielded searching, browsable indexes, customised formatting, metadata extraction (acronyms, languages, etc), a Z39.50 client, and many other features. It supports many input formats, the interface is configurable and multi-lingual, and collections can be distributed on the Web or on CD-ROM.