Want to add your Google Calendar to the iPad's Calendar app? No
problem. In Settings open Mail, Contacts, Calendars. Add an account
and tap on Other. Tap on Add CalDAV Account and enter your Google
Account credentials (the Server is www.google.com). Exit the Settings
app and tap on the Calendar app and all your events should appear. By
default all calendars are displayed, but you can tap on the Calendars
button to choose which ones are shown.
If you would like add additional google calendars to your iPad calendar: go to www.google.com/iphoneselect?gsessionid - Then you can select which calendars you would like on your iPad.