ieSpell - An awesome spell checker for your Webmail or Blog Posts.
If you haven't thought of getting a spell checker for IE, give ieSpell some consideration. Especially on a notebook or Tablet PC where you'll be hitting Web based email from it; or writing your Blog posts from it as I am right now.
Make sure you check out http://www.iespell.com/download.php for a great Internet Explorer spell checker. Works fantastic!