Gmail Growl is a useful utility that was designed in order to bring you instant mail notifications from your Gmail account.
With Prowl support, Gmail Growl forwards alerts as push notifications to your iPhone. Gmail Growl uses IMAP IDLE for Gmail, which provides near-instantaneous alerts of new messages - meaning Prowl's push notifications via Gmail Growl should be about as close to true push as you can get with Gmail on the iPhone.
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