A few weeks ago, the Apple App store for the iPhone gained its first app to manage Google AdWords campaigns. The app was developed by Webdevs.com and enables AdWords advertiser to manage their campaigns on the go. The application can be downloaded in the iTunes store for $16.99 and is named "PPC Editor." If you like to buy it, here is a link which passes through my affiliate account.
This is not an app created by Google. This app uses Google's API to pull data from your AdWords campaign and it was created by a third-party. In my opinion, Google is working on a mobile AdWords interface that will run over the iPhone, Android, Pre, etc but not be application specific. I.e. I think it will be a web based mobile version, to run off the smart phone's web browser.
It seems like the bulk of the features are reporting, but there is management features like changing daily budgets. Here are some of the screen captures from the iTunes store: