I wrote my export script a while ago, back when there was a real need for it for WordPress 2.0-2.1 and Movable Type 3.3. Movable Type 4.X includes an importer for WordPress' content that is exported as RSS data. Anyone switching to Movable Type from WordPress really ought to give that a shot, as it is going to be a lot better supported by Sixapart, than my export script is going to be supported by me these days.
Works like charm. All entries, categories, authors, and comments were imported without problems...
Not quite perfectly. Still has some issues with invalid XML the WP export produces and the biggie for me, it completely ignores WP tags.
I tried it but no so good. Only 1/10 posts could be imported.