A few weeks ago my native iPhone/iPod Touch application for Zimbra was quietly released on the iTunes App Store. Now before you get too excited, I should make it clear exactly what this app does for you as a Zimbra user. :-)
The Zimbra Mobile Web Client for iPhone remembers your credentials and can automatically log you into your Zimbra account. However, this app is *not* a re-implementation of the Zimbra functionality in native iPhone code. Instead, it simply displays the existing standard (or "lite") client in a full-screen web view -- the same interface you get if you were to login using Safari on the iPhone.
This functionality is less needed with iPhone OS 3.0 because Safari now remembers passwords and can auto-fill form fields. But the App Store submission process can take longer than you expect... ;-)
If you would like to try it out, you can find it at the following link:
iTunes Store
I would request that if you find problems with the application that you please send a note to the support email or post to this forum. When reporting an issue be very clear about what problem you encounter and whether it is part of the native settings page or the lite client interface. If the latter, please open a bug for the problem with Zimbra. Thanks!
NOTE: This application is *not* affiliated with, released by, or supported by Zimbra or Yahoo!. This is my personal application.
Bugzilla
Wiki
Source
Native iPhone Application for Zimbra 
Linear Mode
