There are various ways to download Zeal, depending on which operating system you use, and whether you want to use precompiled binary, or build it yourself from source code.
A 32-bit zipped Windows binary with all dependencies included is available
to download from Bitbucket.
Simply decompress the .zip file and run zeal.exe from any place.
If you use Ubuntu Linux Trusty (14.04), you can easily install Zeal from its PPA.
To install it:
apt-get install zeal
For Precise (12.04), Quantal (12.10), Raring (13.04), and Saucy (13.10) there are older versions of Zeal available, but they are no longer supported.
A package in AUR (zeal-git) is available for Arch Linux users, thanks to Whyme Lyu.
There is no rpm package yet, but Zeal can be easily built from scratch. All you have to
do prior the build is to install packages
from the default Fedora repo.
You can also compile Zeal from source code, assuming you have
Qt >= 5.0.0 development tools
installed. Clone the github repository linked below, and run
qmake doesn't work)