This addon allows installing debian packages from iceweasel, firefox, galeon or konqueror just clicking on a web link.
for this to work, links need to have an url beginning with apt:// this package does not install the packages or download them from the web sites, it just launches apt, passing the package name to install as a parameter to apt.
some screenshots to see how it works are available at http://gambas.gnulinex.org/linexapt/