Thanks to Michael, there is now a version of the Leprakhauns Word Count WordPress Plugin, you can get it here. It is the same plugin, it just adds it to the sidebar and adds functionality to be used with pages as well.
[Edit] 11/8/2007 I am happy to announce that it works in WordPress 2.3.1.[/Edit]
[Edit] 7/18/2007 I have updated it so that it will work whether or not you are in the visual editor.[/Edit]
[Edit]There’s an updated version up now. It should work on most if not all versions of WordPress 2.0. Sorry if it didn’t work before.[/Edit]
I created aWordpress plugin that will allow you to write a post and hit calculate and it will tell you how many words you’ve written. It only works in the visual editor, though. I created it because every other word count script I could find was having you save, or post your entry before telling you how many words. Mine will tell you without reloading the page. All you do is upload it to your wp-content/plugins folder.
You can get it here.