Google has added push Gmail to the iPhone and iPod Touch using its Google Sync service, you can now use Google Sync to get your email messages pushed directly to your iPhone or iPod Touch, as well a Windows mobile phones.
The Google Sync service will also sync contact and calendars with your iPhone as well as pushing your Gmail emails directly to your iPhone.
Google’s Sync service uses Microsoft Exchange to push your Gmail to your phone, so if you already using an Exchange account this may be overwritten.
Gmail sync. Get your Gmail pushed directly to your iPhone. Your inbox is always up to date no matter where you are, or what you’re doing.
Synchronize your contacts. Get your Google contacts quickly and easily to your iPhone. With Sync, you can have access to your address book at anytime and place that you need it.
Get calendar alerts. Using your iPhone’s native calendar, you can now access multiple Google calendars, and be alerted for upcoming appointments with sound or vibration.
Head on over to the Gmail Blog for full details on how to set up push Gmail on your iPhone and iPod Touch.