As I understand it, drives can point to any provider, the most obvious being the file system. Thus, "C:\" makes sense at an msh command prompt. However, C:\ is just a pointer to a (filestore) name space provider. Monad extents that to allow you to add other providers. I'm still working out the documentation on how to do this, but one provider that's in the PDC MSH bits is an AD provider. You first have to load the provider, which is not presently done by default, but almost certainly will in later releases. Then you create a drive - in other words an alias to a DN. In my case, I used the alias QANET to point to the distinguished name of "DC=corp,DC=qanet,DC=net".
Once you have the drive created you can simply go 'CD QANET:' and you are pointing to a directory like view of, well guess what - the AD. You can move up and down OUs/Containers, viewing contents, etc. And since all MSH cmdlets are pretty much multi-provider, you can use things like Where (to filter), sort (er, to sort) and format (to format the data).
Another seriously cool feature of MSH is that you can format output as XML. ANYTHING you can generate in MSH can be sent to XML. Do I really have to explain why this is mega-seriously cool?!?!?