SMS = Systems Management Server

SMS is a Microsoft product that is designed to give you control over your desktops in an enterprise environment. You can collect lists of the software that is installed, programs that are running, and the hardware configuration of any given pc in your network. You may also limit the use of specified programs (eg; solitaire) to only run at certain times of the day or not at all.
Possibly one of the more used functions would be remote control. This allows you to take control of a users desktop and scare the bejeezus out of em (sometimes it helps you to resolve an issue as well). Another funky SMS feature is that it allows you to remotely install software, no more going to each users desk with a bundle of cds!

Microsoft┬« Systems Management Server 2.0 includes detailed hardware inventory, software inventory and metering, software distribution and installation, and remote troubleshooting tools. These integrated features make Systems Management Server 2.0 the most scalable way to reduce the cost of change and configuration management for Windows┬« based desktop and server systems. Systems Management Server 2.0 is built on industry-standard management protocols, ensuring compatibility with complementary management tools. Systems Management Server 2.0 is tightly integrated with Microsoft SQL Server™ and Microsoft Windows NT┬« Server operating system, making it easier than ever to install, configure, and maintain Systems Management Server in any size network.

You may find out more information at Microsoft Systems Management Server or online at http://www.microsoft.com/smsmgmt/default.asp