The dotMobi WordPress Mobile Pack is a complete toolkit from dotMobi to help mobilize your WordPress site and blog.
It includes a mobile switcher to select themes based on the type of user that is visiting the site, a selection of mobile themes, extra widgets, device adaptation and a mobile administration panel to allow users to edit the site or write new posts when out and about.
The plugin gives tremendous customisation options. This plugin is what powers the mobile version of this site now. Below are images of the plugin at work on the built-in browser of the LG KS360:
The mobile admin interface is basic, but in my own opinion, that is exactly what is needed for it to be usable on the majority of mobile browsers in the market today.
You can download the dotMobi WordPress Mobile Pack.