Karazeh is a cross-platform tool for patching and launching desktop applications, suited for PC games. The purpose of this tool is to provide you with the ability to update your users' clients with minimal hassle without requiring you to re-invent the wheel and write your own patcher.
Karazeh is meant to be used with Kiwi, the tool that generates the patch scripts which Karazeh consumes. They both should operate on Windows, Linux, and Mac OS X.
Both tools are freely available and licensed under the MIT license.