MMC is, as xdc briely mentioned above is the Microsoft Management Console. It was a part of Windows NT 4.0 as well. It is now the standardized interface for all of the administrative utilities in Windows. The idea is that you use this harness and create snap-ins that easily fit the form and and feel of other administrative widgets, and it makes everything easier to use.

MMC is a lot more transparent and easier to use than it was in NT 4.0. Commonly used MMC snap-ins are Internet Services Manager, or ISM, and the ubiquitous Computer Management snap in, which lets you perform most utilities from one window. It is an effort by MS to make the whole system easier to use, and I know that I for one am grateful for the common interface. MMC is similar to what Control Panels would be under Win9x, but with a focus on more administrative tasks. Certain items are still in control panel format, such as the ODBC / DSN interface.

MMC snap-ins are easily customizable. They allow administrators to easily publish snap-ins for common tasks through the Administrative Tasks menu off of the Programs Menu (if it is enabled, or always from Control Panels).