If the Zoho CRM and Google Apps login credentials are different, you need to add your Google Apps email address as the Primary email address in the Zoho account to integrate Zoho CRM with Google Apps.

To add your Google Apps email address

1. Go to http://accounts.zoho.com 
2. In the Home page, click My Profile Info.
   
3. Under Personal Information click Email Address.
   
4. In the My Email Address page, click the Edit link to change the primary email address.
   
5. Enter your Google Apps Email ID and your Current Password for Zoho.
6. Click Update.
   

Note: The primary email address that you previously had will be listed under your secondary email address.