Earlier tuesday, Microsoft officially announced a new email service, Outlook.com, that’s designed to be a modern version of the company’s Hotmail email service.

Outlook.com sports a fresh design based on the Metro UI and several time-saving features. Users who currently have either a Hotmail or Live.com email account can upgrade their account to Outlook.com (receiving only the new user interface, but not an @outlook.com address). New users can signup for an Outlook.com email address here.

Its new web-based email service, Outlook.com, which replaces Hotmail. Outlook.com comes with a new user interface based on the Metro UI, as well as social networking integration and time-saving features.

According to a recent Tweet from the official Outlook.com Twitter account, the service has already seen one million users signup, in the less than 24 hours it has been available. The number is pretty impressive considering the amount of time, and the fact that Microsoft only launched what it is calling a “preview version” of Outlook.com today. The company says that more features will be integrated in the future.

Have you signed up for Outlook.com?