This recently launched tool from Google is a feature of the new AdWords interface and will show you the potential impact of your bid.
No, this amazing tool does not predict the future, however it does allow you to explore what could have happened had you used different keyword level bidding.
Basically, it uses the past 7 days of data to re-calculate the number of impressions for which your ad could have shown, provided you had chosen a different maximum CPC.
Since click volume and the associated cost are always a factor in managing your pay per click account, this new data could very well provide some good insights into your strategy.
Google has uploaded a YouTube video that helps explain the functionality: http://www.youtube.com/watch?v=jRx7AMb6rZ0