If you are a large enterprise and support multiple different language versions of Microsoft Windows, downloading security patches and keeping track of them can be a nightmare. For example, some security updates are released in over 100 different versions!
To ease the pain of patching Windows in an enterprise like this, you can now obtain .iso images of Windows patches from the Microsoft Download Center. To find these iso images and download them, search the Download Center for "Security and Critical Releases ISO Image" and choose the particular month's patches you need.
Note that these patches are for Windows platforms only, not for Exchange or other products.