Internet Marketing Events, Tradeshows and Conferences
Google Calendar, check this out.
You can create a calendar and then share it out. Other people can then view and see the calendar.
I have moved over several of my calendars to this format and have shared a few. I will be testing over the next couple of months to see how well it works out.
In the mean time, take a look at the Internet Marketing Events, Tradeshows and Confrences calendar I found. Most of these are online, and could be subscribed to easily.