Most Linux distributions have great package managers like apt or portage. But installing programs when you don't have root access can be a pain. You need to find, download and install all the dependencies and their dependencies, setup a prefix somewhere in your home folder and hope that everything works.
Prefixed portage is perfect for those kinds of situations. It's a modified version of portage, the package manager of the Gentoo distribution. I am using it on a computer running Linux, but you can also use it on OS X, FreeBSD and Solaris to install applications and libraries from the portage repository.