apt-get introduction
For those of you new to linux and using a debian based distribution… here is a good introduction to the world of apt-get. Apt-get is a tool for installing software, updating software, uninstalling software and even for doing complete distribution upgrades.
It was the first easy “package installer” frontend to show up in linux distributions that dealt with dependencies “automagically”. It also goes into detail on dpkg as well as the various ways to search for install/remove and upgrade software with apt-get. Apt-get is a command line package installer, there are GUI frontends (like synaptic and aptitude).
These days the apt-get system can be used on non-debian systems as well. Some redhat based distributions make use of apt-get. URPMI is considered analogous to apt-get (as rpm is analogous to dpkg).