Currently Being ModeratedJun 14, 2012 5:40 PM (in response to kae)
When you open the Calendar app, tap the button at the top-left corner (Calendars). That should reveal all the calendars you have available, and you can select/ un-select any or all of them.
If you don't see your 2nd GMail calendar listed, go into Settings/ Mail/ (account name) and make sure you've turned the calendar ON for this account.
Currently Being ModeratedJun 14, 2012 6:07 PM (in response to kae)
You can select which calendars appear on the phone using these instructions: