It’s here: the Microsoft SharePoint Administration Toolkit. This first release contains two tools, both supported on WSS 3.0 and SharePoint Server 2007.

Batch Site Manager
From the “Move, Lock, and Delete Site Collections” page on Applications Management you can schedule bulk operations against site collections in the farm—including moving site collections between content databases (!!).

stsadm extension: UpdateAlert
This command will refresh all alert URLs in a specific site collection, which is extremely important should you change the URL of a web application or after an upgrade.

For more information and links for downloads, have a look at the original article on MSDN: Announcing the First Release of the Microsoft SharePoint Administration Toolkit.