To expand a little, you just need to read the power bricks and see what they support.

Are you taking a laptop computer with you? Every laptop power brick I've seen recently supports at least 110-240v and 50-60Hz. So what I usually do is take the laptop with a plug converter and a handful of retractable USB cables to charge my USB-capable devices (such as iPod and cell phone), and a plug converter or two for a battery charger (camera) or curling iron for the wife.

I've never needed a voltage converter.