The Automattic team released a first look at their WordPress For iPhone App that works on both WordPress.com as well as WordPress.org blogs. The application is Open Source, available from the iPhone App store and will be available for free. The screen real estate problem with the large on screen keyboard looks to be largely solved with this app and it adds the ability to modify previous posts and view your blog on the web. 

More info: ma.tt on iPhone App | Video: WordPress for Phone App