Autodistract

Autodistract is a small tool that will passively protect your privacy online by automatically removing tracking cookies as you browse the Web. If you have Growl installed, then Autodistract will inform you when a tracking cookie has been discovered and deleted. Autodistract is small in size, takes only a tiny amount of memory, runs in the background, and cleans your cookies without touching cookies that are genuinely useful, so it is safe to use.

Requirements:

Any browser that uses the NSHTTPCookie API for cookie storage