Debian unstable's mozilla package includes a script that lives at /usr/bin/mozilla, in place of the actual binary (/usr/lib/mozilla/mozilla-bin.) This script allows mozilla to tell if it's already running, and if it is, to launch a new window instead of launching another mozilla process. The current mozilla package stupidly spawns a new mozilla process every time, thus presenting the user with a profile dialog instead of a usable browser window if mozilla already happens to be open. The script also handles URLs (and decides whether to open mozilla and load the URL or to load the URL in a new mozilla window, depending on whether mozilla is already open), dynamically configures several different variables, and automatically selects the correct mozilla dsp (artsdsp, esddsp, oss, or null) depending on what sound servers the user might be using. It really helps the usablilty of mozilla. If you're interested, I can provide a version customized for arch linux, and/or the orginal debian unstable version. It's a simple bash script. I'm unfamiliar with the mozilla-firebird package; does it provide similar functionality?