Creating Debian Linux packages - Describes the basics of creating Debian packages for distributing programs and source code. This article shows the necessary components of a package and how to put them together to end up with a final product. - http://www-106.ibm.com/developerworks/linux/library/l-debpkg.html
deborphan - Checks for orphaned packages and removes them. Downloads and documentation provided. - http://freshmeat.net/projects/deborphan/
Aptitude - A highly configurable console front-end for Debian APT. Downloads and screenshots provided. - http://aptitude.sourceforge.net/
aptsamever - Lists or removes old duplicate versions of packages installed by apt-get. Downloads provided. - http://aptsamever.sourceforge.net/
Demish - Allows package mirror maintainers to choose which packages they want in their mirror. Downloads provided. - http://luon.net/~admar/
Debfoster - Removes orphaned packages. Downloads and a brief tutorial provided. - http://www.fruit.eu.org/debfoster/