Another resource for alphas is Photoshop Brushes. By using google search you should fine 1,000s of free PS brushes. ZBrush can not import the abr file but there is a freeware program that will open the abr and save the images in the abr file as pngs which then have to be converted to jpegs (or psds) to be used with ZBrush. The freeware is abrMate.
Here used ShadowBox with an created alpha from the abr file.
SpaceMan's Space Book Journal On ZBrush
Wormholes were first introduced to the public over a century ago in a book written by an Oxford mathematician. Perhaps realizing that adults might frown on the idea of multiply connected spaces, he wrote the book under a pseudonym and wrote it for children. His name was Charles Dodgson, his pseudonym was Lewis Carroll, and the book was Through The Looking Glass. ***8212; Michio Kaku
It's kind of fun to do the impossible...
- Walt Disney