I heard about this website on the oh so high brow Kathie Lee & Hoda this morning and had to try it out. You copy and paste an excerpt of your writing (a blog entry, email etc.) and the website uses an algorithm to compare your style to that of famous authors and comes back with a match. It matched me with David Foster Wallace which was kind of a disappointment because, besides the circumstances of his unfortunate end (which received wall-to-wall coverage worthy of the passing of a president on NPR a couple of years ago), I am totally unfamiliar with him.
Anyway, click on the link to see which famous author the software thinks you write like.