Kevin Gibbons spotted some new changes to the Google AdWords Client Center for multiple account management. It appears that you can now create a template and share them with multiple accounts, making it easier so you don't have to port all the changes from one account to another by hand or with a software application.
I'm not even seeing this in the AdWords FAQ yet, so it looks quite new. Kevin has fortunately showed us how to use it in a screenshot step by step on his blog.
It looks pretty useful and should make managing multiple similar campaigns a lot easier.