Managing Mac OS Updates in an Enterprise?

An anonymous reader asks: "What's the best way to manage updates for an office of about 150 Macs of various models with different releases of Mac OS X installed? I would assume the solution involves Apple Remote Desktop Administrator which makes it possible to install updates on client machines without interrupting the user — but then the question becomes how do you keep track of which updates to install? Does Apple have some page squirreled away that lists updates they've released in chronological order with the ability to filter based on OS version and model? Is there an RSS feed or mailing list that announces new updates? For the uninitiated, ARD Admin only lets you install specified packages, so you have to download the updates manually from Apple's website, then queue the packages to be installed on a particular set of machines. This problem would be far simpler if it were possible to simply instruct client machines to run Software Update and install all available updates, or even better, if Apple included automatic update functionality within the OS, a la Windows XP."