It was hinted at earlier in the week with the Windows Live Hotmail update, yes the Windows Live Calendar beta is fast approaching. Its now available to some special people in a dogfood form (pre-beta) at http://dogfood.calendar.live.com/. Unfortunately if you aren't a Microsoft employee you'll just be seeing the MSN Calendar, but at least you now know it really does exist :)
Microsoft needs to deliver a good calendar service to both stem the rapid growth of Google's Calendar and to deliver an all round suite of online services. With software and services being the current buzzwords, we're just hoping it doesn't take another 2 years to see a Calendar desktop application. For those who notice these details, it was pointed out that Windows Live Mail removed the calendar button in the transfer from Mail desktop, however a convenient blank space was left behind for the future.
As was the case with the original Mail beta (now Hotmail), the online Calendar beta service has been written from scratch. While nothing has been confirmed officially yet about the features, talk of .ical support and calendar sharing has been heard.
I guess we might as well start the Calendar beta feature requests now...