When you installed Snow Leopard, you agreed to send this data:
From the EULA:
"B. Location Data. Apple and its partners and licensees may provide certain services through the Apple Software that rely upon location information. To provide these services, where available, Apple and its partners, licensees and third party developers may transmit, collect, maintain, process and use your location data, including the real-time geographic location of your computer. The location data collected by Apple is collected in a form that does not personally identify you and may be used by Apple and its partners, licensees and third party developers to provide location-based products and services. By using any location-based services provided by or through the Apple Software, you agree and consent to Apple's and its partners', licensees' and third party developers transmission, collection, maintenance, processing and use of your location data to provide such products and services. You may withdraw this consent at
any time by not using the location-based features or by disabling the Location Services setting in the Apple Software. The Location Services setting is found in Security preferences within System Preferences. Not using these features will not impact the non location-based functionality of the Apple Software. When using third party applications or services on your computer that use or provide location data, you are subject to and should review such third party's terms and privacy policy on use of location data by such third party applications or services."
Further, the EULA tells you how to disable this. No one is spying on anyone. If you want things like location services to work fast & accurate data like this is a necessary part of the equation.
Everything is disclosed here:
http://www.apple.com/legal/sla/