Some advertisers are noticing a new feature in Google AdWords. The feature is named "bid simulator" and it shows you what number of impressions and position you can expect if you increase or decrease your bid.
A Search Engine Watch Forums thread has a picture of the feature from one advertiser. Here is a screen shot taken from the PDF linked to below:
This seems to have been released on May 20th to some advertisers. Someone posted a PDF document of the reference guide to Google AdWords Bid Simulator. Here is the PDF and below is an embed of it:
Forum discussion at Search Engine Watch Forums.
Update: Google sent me a statement about this, saying:
As part of our ongoing commitment to innovation, Google constantly tests new tools to improve our AdWords product offering and provide additional benefit to our advertisers. We are currently testing a feature called "bid simulator," which helps advertisers make informed and efficient bid management decisions by estimating the results they would have achieved using hypothetical bid values. This feature is currently in a limited beta with a small number of advertisers. We have no additional news to announce at this time regarding developments for Google AdWords.