You can now use Google Ad Planner to share Google Analytics data. "By sharing this Google Analytics data with Google Ad Planner, you'll ensure that potential advertisers will see this critical information, feel confident in the accuracy of the data, and make better-informed decisions about including your site in their media buys."

http://adwordsagency.blogspot.com/2009/05/more-accurate-google-ad-planner-data.html
http://www.google.com/support/adplanner/bin/topic.py?topic=20288