Pidgin is a GTK+ instant messaging application for Windows and Unix. It supports AIM, ICQ, Jabber/XMPP, MSN, Yahoo!, Bonjour, Gadu-Gadu, IRC, QQ, SILC, SIMPLE and more. See http://pidgin.im/about for more information.
XAMPP is a very easy to install Apache Distribution for Linux, Solaris, Windows and Mac OS X. The package includes the Apache web server, MySQL, PHP, Perl, a FTP server and phpMyAdmin.
The IPCop Firewall is a Linux firewall distribution. It is geared towards home and SOHO users. The IPCop web-interface is very user-friendly and makes usage easy.
wxWidgets is a free C++ framework that facilitates cross platform software development, including GUIs, threads, sockets, database, file system access, etc.
Fink is an attempt to bring the full world of Unix Open
Source software to Darwin and Mac OS X. Packages are downloaded and built automatically and installed into a tree managed by dpkg, all with full dependency tracking.
net-snmp provides tools and libraries relating to the Simple Network
Management Protocol including: An extensible agent, An SNMP library,
tools to request or set information from SNMP agents, tools to
generate and handle SNMP traps, etc.
A very high quality package of printer drivers for Ghostscript and CUPS on Linux, Macintosh OS X, and other POSIX-compliant operating systems. This project also maintains an enhanced Print plug-in for GIMP 2.x from the same code base.