More pictures can be found here.

Unfolded and edited by me, but the original 3D model is (c) Blizzard Entertainment 2008.

Whew, finally stopped being lazy and made the .pdf!

Click "download" for a .zip containing the .pdf and .pdo for this model.

The .pdf can be opened in Adobe Reader (which can be downloaded for free on the Adobe site if you don't have it already), and the .pdo can be opened in Pepakura Viewer (also free, but Windows only).
Pepakura Viewer is much easier to build it with, since it shows you a 3D model next to the unfolded version (which, unless I'm mistaken, you can add things like edge numbers and whatnot to make it easier to understand - if I'm wrong and this is only in the Designer version (costs money), tell me and I'll re-upload this with a .pdo with numbers.

The unfold might be a bit messy, sorry about that. I got really angry when I closed Pepakura Designer and forgot to save (I had just reorganized everything nice and orderly), and I didn't realize that before I hit no in the save prompt
So I lost the nice version, but I managed to make it from the current one so it shouldn't be too bad
Sorry that the whole model of the helm is in the .pdo, I was too lazy to unfold/edit a whole new model with the cloth left out. Just ignore the mess of red on the last page, it doesn't interfere with the skull itself in any way.

If you have any questions about this model or papercraft in general, feel free to ask!