This is far from the first attempt at incorporating a bottle opener into an iPhone case. But the Fortress 2 from XGearlive is hands down the only design you should consider. Instead of a clunky slide-out mechanism, or an unsightly bulge on the back, it neatly integrates a subtle opener onto the edge of its bumper case form factor.
At $100 you have to love your bottled brew, particularly since you can open a beer for free on the edge of a counter. But if you're also looking for some tough lightweight protection, the Fortress 2 is made from aircraft grade aluminum so it should be quite effective at protecting your phone. And thanks to a quick-release mechanism on the bottom it's easy to install, or remove, if you ever decide to go sober. [XGearlive via Technabob]