Sync your BlackBerry's mail, contact, and calendar apps with your Google Apps account using your mobile carrier's BlackBerry Internet Service (BIS).Follow our instructions, but for more support, please contact RIM.
If your company has a BlackBerry® Enterprise Server (BES), follow these instructions to sync your BlackBerry's mail, contact, and calendar apps with your Google Apps account (applies only if your organization is using Google Apps Connector for BlackBerry® Enterprise Server).
Use Google Talk for BlackBerry® (supported by BlackBerry)
BlackBerry provides a Google Talk client that you can download to your device here:
Then chat with your Google Talk contacts directly from your BlackBerry. Learn more