I'm happy to announce that you can now login to and purchase Windows Azure using "organizational accounts". Up until today, users have only been able to login using their Microsoft account (formerly Windows Live ID)
For corporations, organizational accounts have several key benefits:
Employees do not have to sign in with 'personal' accounts e.g. with their Microsoft account. You can cleanly separate personal assets from organizational assets.
If an employee leaves the company, the employer can revoke their account without having to call Microsoft support.
If you have set up federated authentication with Microsoft (e.g. using Active Directory dirsync), your users can log in using their domain credentials! This is really powerful, because you remain the sole owner of your users' identities.
If you have signed up for Office 365, you can login using the same credentials.
Last but not least, users can now login using two-factor authentication such as a smartcard.
There are a few limitations, which we are working hard to remove: Enterprise Agreement customers cannot yet login with organizational accounts, they have to continue to login using Microsoft accounts.
If you have Office 365, sign in to Windows Azure using your domain e.g. https://manage.windowsazure.com/contoso.com (replace contoso.com with your real domain).
Try it out and let me know what you think!