Open up your Outlook calendar, click the Home tab on the Ribbon, and under Manage Calendars click on Open Calendar \ From Internet…
Now enter the link location into the New Internet Calendar field then click OK.
FOR EXAMPLE: Main Horley Calendar
Click Yes to the dialog box that comes up verifying you want to subscribe to it.
If you want more subscription options click on the Advanced button. Here you can name the folder, type in a description, and choose if you want to download attachments.
That is all there is to it! Now you will be able to view your Google Calendar in Outlook 2010.