Windows Live have a feature called Live Groups. This is a groupware for small community which have among features, shared calendar and discussion board.
Although the useful feature, there is a shortcoming in this. As any such online service, you’ll need a Live ID.
But if what you need is simply sharing your personal calendar, you can also use Live Calendar.
First, in your Live Calendar, click the “Share” in the menu. It will bring out list of your Calendars. For this example, I choose my main calendar.
You will then be redirected to this page. Choose depend on your need.
If the peoples you want to share to had Live ID also, you could choose the first option. You can send them e-mail with invitation. You can specify what they could see also. If they accept the invitation, they will add an imported calendar (yours) to their own.
- View events: read-only access. They can see the detail of your events (except privates) but can’t edit.
- Only view Free/Busy time. They can only see if you’re free or busy at a specific time without details of what made you busy. Enough to plan an event and check if you’re available.
- View, edit and delete events. They can do anything except making new events.
- Make them co-owner. Same as above plus access to create new event.
Here is what if you want to share to the more general public. There are three options, HTML, ICS and XML. The links are not active yet before you save your settings.
- HTML link shows a read-only view of your Calendar.
- ICS link can be imported into other calendar application, such as Outlook, Windows Calendar, or in other online service such as Yahoo or Google.
- XML link can be viewed in RSS reader.
After you save, you could send the link by e-mail, IM, post-it notes or dictate it through phone, although the last two doesn’t sounds like a good idea.
The possible application for this is… sharing your calendar. Imagine, sharing your calendar with family or close friends. They could check when you’re free before making invitation, or decide the time after considering everyone’s free/busy schedule.
Groups calendar is better if you only want to share group related events, but it’s also more convenient to share to many at once.
The shortcoming of this is, on the receiver side, they will add another calendar to their own. If they take dozens of such share, it will be cluttered. Outlook with Exchange do better in this. 
