Users of Google Apps or personal Gmail can take advantage of the free service offered through Google Sync Google introduced on Tuesday push e-mail for iPhone and Windows Mobile devices, stepping up its enterprise offerings.The push e-mail service is available through Google Sync, the technology that already pushes contacts and calendars to phones. Google Sync is free for Google Apps customers.Administrators can enable push e-mail through the Google Apps control panel, although if companies are already using Google Sync for contacts and calendar, the e-mail feature is automatically enabled, Raju Gulabani, product management director at Google, wrote in a blog post. People using Gmail and Google Calendar with personal accounts can also use Google Sync to push e-mail and calendar updates to their phones.Users can choose to sync contacts, their calendar and e-mail or any combination of the services.Google already offers a connector service that integrates with the BlackBerry Enterprise Server to push Google Apps e-mail, calendar and contacts to BlackBerry devices. Push e-mail for iPhone and Windows Mobile phones is the latest attempt by Google to move into the business market. It is competing with many well-established providers of push e-mail, including Microsoft and Research In Motion. It is also competing with a number of third-party companies like Good Technology that offer companies a single platform that can push e-mail and other corporate data out to a variety of cell phones. Technology Industry