As you can see Moodle has it's own default calendar but unfortunatly you currently can't import a web calendar into the Moodle calendar. I use a Google calendar as part of my Google Apps (learnscapepro) so I have decided to create a page and embed my Google calendar into it.

If and when Moodle add this functionality to their calendar I will move back to it. You can find the link to my calendar page under "Main Menu" or below here.

Calendar