I have release WP-EMail 2.10 for WordPress 2.1 only.
Note: If you get 404 error even after re-generating permalinks, it means that your theme is using an outdated way of getting/display posts from the database. Just drop me an email with your page.php from your theme folder attached.
There will be no more integrating of wp-email to your theme, everything is automatic now, you do not even need to create a page for this.
I have also internationalize this plugin which makes localization much easier.