Keep It All in Sync
Google Calendar can import data from other calendars in the iCal or CSV (comma-separated values) formats. This comes in handy if you plan on migrating your schedule to Google once and forever. But for people who want to use both Google and Outlook, Google makes a utility that keeps data from both sources in sync with each other.
Import from iCal or Yahoo: To import data from a calendar, you must first export it to a file. For example, in Apple iCal, select the calendar you want to export and choose File, Export. Then name and save the file. In Yahoo Calendar, click Options on the upper right and then click Import/Export under Management. Click the Export button under 'Export to Outlook'. Save the file to a desired location.
Import from Outlook: Outlook users have more than one option. If you have a single calendar in Outlook, it's probably easier to import the data using Google's syncing utility (see "Google Calendar Sync," below). But if you have multiple calendars in Outlook, you're better off exporting them to a separate file one at a time. To do that in Outlook, choose File, Import and Export and select Export to a file. Click Next and select Comma Separated Values (Windows). Click Next, select a calendar, and click Next again. Continue to follow the steps in the wizard. When you're prompted for a date range, Google recommends that you specify no more than one year's worth of data. You may need to repeat the export process for each year that you want to export, importing them into Google Calendar one at a time.
Once your data is saved as a file, go to Google Calendar, click Add below the minicalendar on the left, and choose Import Calendar. In the Import Calendar tab, click Browse to locate and select your calendar file. Then use the drop-down list to specify which calendar should receive the data. Then click Import.
Google Calendar Sync: Outlook users who want to use Google's syncing utility can download it from this link. Once you have saved and finished downloading the file, run the installer. As part of the installation, the program will instruct you
Google Calendar Sync is an easy, painless way to make sure that your Outlook and Google calendars always have the same information. But the tool can synchronize only your default Outlook calendar and your main (first) Google calendar. For many people, that's enough.