An application by the name of Little Snitch will help you control the transmission of data over the internet. It’s a small application which serves as a firewall and monitors all outgoing network and internet activity. This will make it possible for you to monitor applications which “phone home,” stop any spyware which might be at work, and generally allow you to know which applications are connecting to the net without your knowledge (ahem—iTunes—ahem).
A free trial of the software gives you three hours of protection. After that it’ll cost you $24.95, which is a steep price to pay unless you’re really paranoid.
"ahem-iTunes-ahem"
Even Dashboard.
I'm an avid Little Snitch user, and couldn't be happier with my purchase of it. Little Snitch is one of the first things I install on my new Macs. Getting it trained can take a few days as things pop up and ask permission, but once it's done, you can work with complete confidence that nothing is going on behind your back.