SITE NOTICE | MORE..WordPress Widget v1.6! New, CSS-friendly version of the Sermon Browser is now available with further customization. Please note that updating from the previous version will reset all of the saved widget settings. .. click for more info!
You have to make sure you go to the "code" section and paste it there. There is typically a button labeled "HTML" on the content sections and will show you the raw code. If you paste it there, you won't see it in the editor, but will when viewed in the live site.
One wordpress site that uses it: http://indyfpc.org uses both a widget for the sidebar as well as for the "sermons" page.