The Tabbed Windows Extension allows you to manage multiple documents using tabs, and it works in the pretty much same way as the Tabs feature in Firefox. The current version of the extension offers only limited functionality, and it's still rather buggy. In fact, the author considers it a working demo rather that a ready-to-use extension. Nevertheless, it offers a pretty good idea what a tabbed interface may look like in OpenOffice.org.
Figure: Tabbed Windows Extension