News of a planned premium version of Microsoft's Outlook email platform broke a couple of months back, but at the time it was merely described as a pilot program. Thanks to a landing page discovered by Paul Thurrott, we know now Microsoft's subscription-based service will cost users $3.99 per month. For the price, Outlook.com Premium will give users an ad-free inbox, better calendar sharing and the ability to choose up to five custom email address domains. So if you're a fan of Outlook, but not so down with an outlook.com or hotmail.com email address, this could cure what ails you.