Google just began offering their AdWords Editor in beta, to selected advertisers.
From the AdWords Editor website:
AdWords Editor currently is available only to a limited number of advertisers. If you aren't a beta participant, please be assured that we're working to release AdWords Editor to a larger number of advertisers in the near future.
According to the description on Google AdWords Editor website, the AdWords Editor is a downloadable account management application for one's computer and is designed especially for large AdWords accounts where it allows one to make changes to their account with greater ease and flexibility. "Download your campaigns, make bulk or individual edits offline, then upload your changes to your AdWords account".
6.5MB in size and downloadable in 30 seconds over a broadband connection, AdWords Editor works the same way as GTalk does when it comes to updates, which is done automatically. As of now, the AdWords Editor has only been tested on the Home and Pro editions for Windows 2000 and Windows XP, however, Google says that the application is designed for cross-platform functionality and they're working on expanding functionality to Mac & Linux!