Ubuntu Hardy ships with Pidgin v2.4.1 and Firefox 3.0 Beta5, while the latest Pidgin is v2.4.2 and the latest Firefox is 3.0 RC1. Here are two repositories that would always contain the latest versions of Pidgin and Firefox. Just type “gksu gedit /etc/apt/sources.list” into the terminal, and add the following to the end of the file.
deb http://ppa.launchpad.net/pidgin-developers/ubuntu hardy main
deb http://ppa.launchpad.net/mozillateam/ubuntu hardy main
After adding the lines, just type “sudo apt-get update” and then “sudo apt-get dist-upgrade” in the terminal (apt will give a warning about unauthenticated packages, but its safe to ignore the warning and type “y”). After doing this, you should have the latest versions of both Pidgin and Firefox 🙂