Microsoft and Lawrence Lessig's Creative Commons organisation have unexpectedly teamed up to develop a tool that lets Microsoft Office users create Creative Commons licences from within Microsoft Office documents.

Creative Commons licenses allow an author of published material to decide how he or she wants to allow others to republish or reuse that work.

The new copyright licensing tool will enable people creating documents in Office, PowerPoint or Excel to immediately attach a Creative Commons licence to the document through an option in the applications' "File" command, said Tom Rubin, a Microsoft associate general counsel for intellectual property.

The tool will be available Wednesday as a free download on both Microsoft's website and at the Creative Commons site.

Currently, copyright law "operates automatically to say the author reserves all rights to himself," said Lessig, a law professor at Stanford University and founder of its Center for Internet and Society.

The objective behind a Creative Commons licence is to "provide a simple way to say, 'Here is the freedom you have to make derivations [and changes] while I continue to have some rights to myself,' " he said.

This kind of freedom is especially important for material published on the Internet, which, since it is in such a public domain already, may not necessarily need the same kind of restriction as a book or journal article, Lessig said.

Though Rubin said Microsoft has teamed up before with Creative Commons on some smaller projects, the pairing may seem surprising to many, as there is little love lost between Microsoft and Lessig.

The company's claims that Lessig was biased against it caused the attorney to lose his job as an advisor - or "special master" - to Judge Thomas Penfield Jackson during the Department of Justice's antitrust case against the vendor.

Since then, Lessig has been outspoken in his view that Microsoft should have faced a harsher sentence in that case.

"It's an interesting set of bedfellows," noted Rob Enderle, analyst with The Enderle Group, in San Jose, California. "Lawrence Lessig hasn't exactly been a great Microsoft fan."

Still, the partnership has positive implications for both sides, he said. Lessig wins a significant partner in his push for removing some of the restrictions from copyrights, and Microsoft offers a useful tool that will make current and potential Office users happy, Enderle said.

Lessig founded Creative Commons in December 2002, and today there are about 140 million published works - which include audio and video files, as well as documents and other printed materials - that use a Creative Commons license, he said.