Opting Out of Targeted iAds
Apple (via Apple Insider):
Apple and its partners use cookies and other technologies in mobile advertising services to control the number of times you see a given ad, deliver ads that relate to your interests, and measure the effectiveness of ad campaigns. If you do not want to receive ads with this level of relevance on your mobile device, you can opt out by accessing the following link on your iOS 4 mobile device: http://oo.apple.com. The message "You have successfully opted out" will appear and you will be automatically opted out of interest-based ads.
[...] transmitted from your phone to Apple for iAds or how long Apple keeps the information. You can opt out of interest-targeted iAds, but this does not apply to the location tracking. It’s not clear whether your location data [...]