My apology, Swanson and others. I was making an incorrect (and unwise) assumption that folks here would be aware of the Inside AdWords blog post from earlier today, since it was mentioned in another thread on the same topic.
Due to the WebmasterWorld's charter for the AdWords forum, I am not able to link to it - but it is easy to find. Or, even better, perhaps another WebmasterWorld member who is not also a Google employee will link to it. ;)
At the bottom of that post is a link that directs you to a number of FAQs on this subject, which I will also link to here: