Finding domains from same owner

Does anyone know of a free tool like sameowner.com or addsspy.com ?
One that lets you find sites that have the same adsense ID on them?

Don't really know how to find the adsense ownership of other websites (tried a search with the Pub. ID, no joy) without knowing the URL and doing a WHOIS on it.

Second best choice could be a 'reverse IP lookup' i.e. www*yougetsignal*com/tools/web-sites-on-web-server/ this will tell you what sites share the same server and IP.

* in URL = .

Hope this helps. If you do find an answer I would appreciate the info. myself.