The Library Creator allows you to create your own instrument libraries.
These instrument libraries can be distributed between computers using Steinberg’s Library Manager. A library can consist of either a single VST Sound container or a combination of VST Sound containers. VST Sound is a Steinberg container format comparable to ZIP or ISO files, for example. It contains a file structure with folders and files. Once a library is registered in the MediaBay, its containers are mounted, and all Steinberg products that contain a MediaBay can access the folders and files within the library.
For further information, go to: Steinberg Developer Resource.