I am looking for a way to sync a website's calendar events to a user's personal calendars such as Outlook 2003/2007, Google Calendar, Apple iCal, Windows Calendar, Yahoo! Calendar, etc.
There was a company that provided this exact service, by the name of FuseCal, however they went out of business a few years ago. I have not managed to find an alternative company which provides the same service. You can read more about FuseCal's features here
I would really appreciate it if you could recommend me some other software or ways to have this functionality on my website.