Dar is a shell command that makes backup of a directory tree and files. Its features include splitting archives over several files, DVD, CD, ZIP, or floppies, compression, full or differential backups, strong encryption, proper saving and restoration of hard links, extended attributes, file forks, Door inodes, and sparse files, remote backup using pipes and external commands (such as ssh), and rearrangement of the "slices" of an existing archive. It can run commands between slices, before and after saving some defined files or directories (for a proper database backup, for example), and quickly retrieve individual files from differential and full backups. Several external GUIs exist as alternatives to its CLI interface, like kdar, DarGUI, SaraB, etc.
With 'nixstaller' you can easily make installers for Unix-like systems. Some of the project goals: support for many different platforms, support for different (optional) frontends used by the installer (currently FLTK, ncurses, GTK 2, and Qt are planned), ease of use for the install creator and the end user, different ways of installing (extract files to a location, compile software on the user's system, and maybe even integration for the package manager running on the user's system). Nixstaller can be fully translated and is programmed in C++ and sh.
pkg++ is a tool to build packages. The goal is to provide a tool you can use to build a package from a generic recipe on your distribution/OS and for your native package manager. The recipes, when done correctly, can be used on multiple OSes, and thus users can share them even if they do not use the same distribution. It is as much a way to easily package as it is a way to create multi-OS package recipes repositories.