Google Tutor, a blog full of Googley-goodness, has come up with a quick way to identify a site's owner - just snoop on their Adsense ID.
It's pretty easy. All you do is a quick view-source and look for the keyword "client". Sometimes you'll be able to ID the owner by the text attached to this word; if not, you can CTRL-C the numeric code and Google it to see what other sites that particular code belongs to. Of course, this will only work on sites that are using Adsense on their pages, but it's still a pretty useful little hack.