Vertigo
Vertigo 0.5 for Windows
Tee Yen Ng Browser & Email / Browser Tweak
Vertigo is a Firefox add-on that will replace your horizontal tabs with vertical ones

Software Summary:

You can run Vertigo on Windows operating systems. Vertigo is a software product developed by Tee Yen Ng and it is listed in the Browser & Email category under Browser Tweak. Vertigo is a free software product and it is fully functional for an unlimited time although there may be other versions of this software product.

Alternatives in Browser & Email on Windows