It turns out that including javascript inside individual posts in Wordpress 2.0 is annoying because of the automatic text and character formatting that the software applies. The best solution seems to be to install the Text Control Plugin, which allows you to specify the text formatting post-by-post. If you want to include javascript in the post, you’ve got to turn off the formatting altogether, which doesn’t change the look of the post at all, you just have to make sure you used all the right HTML tags. (e.g. you marked each paragraph with a paragraph tag)
(References: chenggn.com, Wordpress Codex)

Note: One quirk of the Text Control plugin: you can’t actually change the formatting options for a post until after you’ve saved it (or published it). So you create the post, click ‘Save and Continue Editing’ and then two additional drop down menus appear towards the bottom of the post editing page.