Raanan recently announced the release of the iPhone app, WordPress 2.2. This not a major release, but a minor release. It does add some much wanted functionality though.
Notable, these are the major feature upgrades:

Reply to Comments
Edit Comments
Highlighting the new items in the comment list

Click here to download the upgrade: WordPress 2.2 – …

Version 2.0 of the WordPress iPhone application [iTunes link] is available.

Here are a few things that are new with version 2.0.

A new, more efficient user interface that makes it faster to switch between comments, posts, and pages.
Various user interface refinements and bug fixes
New comments interface, with Gravatars and the author URL shown in the comment …