Back in 2000, I wrote a small software utility called deborphan to make my system a little more manageable. deborphan searches for packages (libraries specifically, but also packages in general) that are no longer in use on a Debian GNU/Linux system.
After moving abroad I stopped maintaining deborphan, and it is now being maintained by Peter Palfrader of the Debian project.
You can find the source and Debian packages on the packages.debian.org website. Bug-reports, questions, etc can all be directed directly to the package maintainers.
