Apple says that the data is “collected anonymously in a form that does not personally identify you,” but for some reason we don’t find this very comforting at all. There appears to be no way to opt-out of this data collection without giving up the ability to download apps.
Here’s the full text:
To provide location-based services on Apple products, Apple and our partners and licensees may collect, use, and share precise location data, including the real-time geographic location of your Apple computer or device. This location data is collected anonymously in a form that does not personally identify you and is used by Apple and our partners and licensees to provide and improve location-based products and services. For example, we may share geographic location with application providers when you opt in to their location services.
Some location-based services offered by Apple, such as the MobileMe “Find My iPhone” feature, require your personal information for the feature to work.