Google Calendar

Google Calendar has a new-to-me feature of being able to sync with Microsoft Outlook.

You can choose to sync both ways, Outlook appointments to Google Calendar, or Google events to Outlook Calendar. You can also choose how many minutes should pass between syncs. I tried it out (syncing Google Calendar with Outlook appointments), and was disappointed to find that it only synced with appointments that I had created, not ones that I have been invited to and accepted. So, I quickly uninstalled it. Though I wouldn't suggest using the sync application, a good feature that I did discover (not in any way connected with the sync application) is that if you invite your Gmail account to an appointment while setting it up, it will automatically add the event to your Google Calendar.

Find out more about Google Calendar Sync