Marco, this great guy and talented web-dev from Netherlands (spelled ?????»?°???????? in Bulgarian, as in Holland), has a great intro to xajax. If you're browsing around to pick an AJAX library that suits you best, this is a must post to check out.
On a different note, apparently Marco never sleeps, because he just finished a theme for a Typo contest (Typo is a blogging software, very AJAX-rich) and his blog just became a part of the 9rules network. Keep an eye on this guy (and that rhymes! ðŸ™‚ ) as I get the feeling we're going to see more from him in the coming months. And that doesn't mean you shouldn't consult his past posts, because you should, great stuff there.
And on a completely different note - I was this close of carrying the family name "Markov", my father's family name used to be Markov after a grand-grand-...-grand-father whose first name was Marko (or Marco) but my father changed his name to Stefanov. This close... ðŸ˜€