may i also recommend pbuilder which makes backporting easier by providing an easy-to-manage
pristine chroot environment for building packages.
using pbuilder on my testing/"lenny" desktop, i backport applications for servers running
stable/"etch" and even desktops running ubuntu hardy/8.04.
i also use apt-proxy for caching packages for both pbuilder and other machines, but it's not
that specific to backporting or pbuilder.