OpenOCD is available in many different forms from numerous places, this page should serve as a guide directing you to the option most appropriate for the usecase.
When reporting a bug or asking for assistance via any medium (such as the mailing list, IRC or the issue tracker) please state unambiguously which version you’re using and where you have got it from. If you are not prepared to recompile from the sources (that’s often needed to test out-of-tree patches), please mention that too.
Official operating systems’ repositories
OpenOCD fits the free software ecosystem naturally, so it is available in a properly packaged form in popular operating systems in their respective repositories. In other words, installing OpenOCD is as easy as running an
apt-get install openocd command in Debian GNU/Linux (and derivatives),
emerge openocd in Gentoo,
opkg install openocd in OpenWrt etc. Same applies to OS X users running Homebrew (or MacPorts) and Windows users who have MSYS2 installed.
If your OS of choice is missing OpenOCD, please feel free to become a package maintainer, the OpenOCD community will appreciate your involvement and provide assistance should you face any issues.
A number of the patches proposed for inclusion upstream but not yet committed are available from the Gerrit review server.
Unofficial binary packages
Some special circumstances might make using a package manager or self-compiling OpenOCD impractical, so several nice community members provide regularly updated binary builds on their web-sites.