You'll need a large black robe. It buttons across to the right side, so what you wear underneath doesn't matter.
- Use this Jedi robe tutorial to make a set of flowing robes. Just don't make the tunic that goes underneath. Voldemort is no Jedi.
Again, the robe pretty much takes care of any other clothing issues. Wear a pair of black slacks, or make your own simple black drawstring pants.
Voldemort appears without any shoes, but I would suggest to instead go with a pair of hefty black boots. Even black sneakers will work in a pinch, and for kids.
There are some ridiculous Voldemort masks out there, but they don't really strike fear into the hearts of anyone because they look too fake. Applying makeup means that you won't have the same nose as Voldemort, but it tends to look better than a mask, anyway.
Use a sponge to cover the face in white to simulate Voldemort's pale skin. Add subtle hints of blue to tint the temples, jawline and a touch under the eyes. Apply a touch of red at the corners of the eyes and under the eyes as well. Make sure you blend the red and blue into the white so that the tints of color appear natural.
Well, a lack of hair, really. I suggest getting your hands on a bald cap from your local costume shop. Otherwise, slick your hair back with gel and keep the hood of your robe up so no one is the wiser.
I wanted to add a note here because there are some silly rubber gloves selling as part of Voldemort costumes. While J.K. Rowling writes about the extreme length of Voldemort's fingers, I suggest that you just apply a set of fake fingernails and leave it at that.
Rubber hand gloves are not only unsightly looking, they also present a problem when you are trying to pick up or hold just about anything.