SkyDrive users can now share Office documents with anyone | Webware - CNET

No Passport required...

"Using Microsoft's Office Web Apps or Office 2013, you can create a URL of any document that you store online. You can then e-mail that URL to anyone who needs to view or edit your file. Previously, that process required your collaborators to sign in with a Microsoft account before they could tweak your document. Now that restriction is gone.
Users who receive the URL to your document can click on it to view the file in Office Web Apps. From there, they simply click on a link in the Web app to edit the file in the browser. The file opens in the associated Office Web App without prompting for a log-in account, where your collaborators can then edit and resave the document."

SkyDrive users can now share Office documents with anyone | Webware - CNET