My friend in SoCal, a THO buddy, just told me about Technorati.com, a site he found in Hugh Hewitt's book Blog!
I don't know everything the site does because I haven't looked at it for very long, but the primary function seems to be tracking which sites are being linked, and from where. It's kind of like a "trackback" feature, but for any site you want to check.
I used it to find out who's been linking to my blog, or to The Holy Observer. It's pretty nifty. If you've got a site, give it a try.