Yesterday, Google launched an Android App for AdWords advertisers to manage aspects of their ads. The Android app is over here in the Google Play store and is available as a free download. In short, it gives you limited functionality over your campaigns including:

View campaign stats
Update bids and budgets
Get real-time alerts and notifications
Act on suggestions to improve your campaigns
Call a Google expert

Here are pictures of some of the app screens:

You have to assume an iOS app is coming soon.

Forum discussion at Google AdWords Help and Google+.