HOWTO: Enabling tab restore previous session in Firefox2
Firefox 2 already have a session saver built-in with the browser. However, it only activates when firefox crashed. Theres no available menu in the firefox preferences to adjust this behaviour, and some of us might want Firefox to restore tabs from our previous session. Fear not, you can still adjust it by editing a key through the about:config interface and enable the built-in restore previous session functionality.