One by one, MSN is starting to charge for formerly free services. (Guess this is a way to make up for the loss of dial-up subscribers….) Now it's MSN Calendar that is moving from free to paid, reports Windows enthusiast Steven Bink on his site today. Just as the case with MSN Photo, Calendar users must subscribe to Microsoft's MSN service in order to continue to access MSN Calendar. Non-subscribing Calendar users have until June 25 to pony up.