"The term w00t is a slang interjection used to express happiness or excitement, usually over the Internet.
Leet is characterized by the use of non-alphabet characters to stand for letters bearing a superficial resemblance, and by a number of quasi-standard spelling changes such as the substitution of "z" for final "s" and "x" for "(c)ks"." from Wikipedia

Adam Rifkin posted today on his blog an entry about w00t! and leetspeek, before read about them on 8 Ways to Sunday. You can read more about w00t and Leet on Wikipedia and on my entry about leetspeek. After read those links don't forget to convert any web page into l33t5p33k, as Adam said, like my 8181'5 80x.