You can move appointments (and contacts) from a pst file into the Calendar (or Contacts) folder just by dragging them. If you added the account to Outlook desktop, it will be listed as Microsoft Exchange account type in Account Settings. Note that this is supported in Outlook 2010 or newer.
I would like to export my Outlook calendar to the calendar at Live.com. How do I do this?
It’s actually very easy to do. If you have your Outlook.com account set up in Outlook as an Exchange server account (you need to use autoaccount setup) then you can copy or drag the appointments from one calendar to the other.
To drag the appointments to the Outlook.com Calendar folder in Outlook: Use a List view on your calendar, Select All (Ctrl+A) and using the Move to Folder command (or Copy to Folder) or drag them to the Outlook.com calendar in the folder list.
Import the Calendar
If you are using an older version of Outlook and are unable to connect it to Outlook.com as an Exchange account, you can save the calendar as an .ics file and import it into Outlook.com.
The maximum file size you can import is 10 MB.
To export the calendar as an .ics (iCalendar) file, select the calendar folder in Outlook, click File, Save Calendar.
If you don’t change the options under More Options, the exported calendar will be Availability only, Today only. Most people will choose Whole Calendar as the Date Range and Full Details.
Click Show (it is clicked in this screenshot and now says Hide) if you want to include details of private appointments. Note: Don't select Include Attachments, Outlook.com doesn't support attachments at this time.
Log into your calendar at Outlook.com, then click Add Calendar and choose From file.
Browse for the ics file you exported, select the calendar it should be imported into and click Save.