Munki is a set of tools that, used together with a webserver-based repository of packages and package metadata, can be used by OS X administrators to manage software installs (and in many cases removals) on OS X client machines.
Munki can install software packaged in the Apple package format, and also supports Adobe CS3/CS4/CS5/CS6 Enterprise Deployment "packages", and drag-and-drop disk images as installer sources.
Additionally, Munki can be configured to install Apple Software Updates, either from Apple's server, or yours.
Munki is currently in use at organizations all over the world, managing software for tens of thousands of Macs.
Get started with Munki here: Getting Started with Munki
If you have questions, or need additional help getting started, the munki-dev group is the best place to start. Please don't post support questions as comments on wiki documentation pages.