Google's official mobile blog has just (and finally!) announced Push Gmail support for the iPhone!

Integrated into their existing GoogleSync service, which up until now supported only contacts and calendar, now:

Using Google Sync, you can now get your Gmail messages pushed directly to your phone. Having an over-the-air, always-on connection means that your inbox is up to date, no matter where you are or what you're doing. Sync works with your phone's native email application so there's no additional software needed. Only interested in syncing your Gmail, but not your Calendar? Google Sync allows you to sync just your Contacts, Calendar, or Gmail, or any combination of the three.

One big caveat remains, however. GoogleSync is powered by Microsoft Exchange ActiveSync, and most devices -- including the iPhone -- can only handle one (1) EAS account at a time. So, if you're already using Exchange ActiveSync for your corporate email, that slot is taken and GoogleSync is useless to you.

For everyone else -- joy! And if you try it out, let us know how it works for you!

[Thanks to mattshall for the head's up!]