IE-only websites are an unfortunate reality on the net. They are especially prevalent on the corporate intranet where I work, where the slogan "thou shalt only use IE" is seen in full effect. I use Firefox as my primary browser, and was getting really tired of having to constantly switch to the desktop, find IE, copy & paste an URL from Firefox, and continue browsing in IE.

This is a Firefox extension that auto-saves all tabs when you exit and reloads them when you restart Firefox. Very nice. You probably want to read the user comments at the site linked below, because it sounds like it may have a few weird behaviors (not to mention the confidence-inspiring "version 0.2" label ...).

Link: Firefox Session Saver

The "Developer notes" on the above site recommends getting a newer version from the author's homepage, but it seemed out of date. Hm. The linked version works fine for me.