In case you ever wished for one - there is a spell checker for your posts on OlyBlog, although it isn't as convenient as it might be. If you click the little link that says "Disable rich-text" below the editing window, it switches to a different view of your post. That view shows all the HTML tags in between brackets like <....>, which can be rather messy, but it also underlines any words that fail the spell checker in red. It seems to work quite well, and it updates dynamically, so if you change the word to the correct spelling the red underlining vanishes. (Sometimes this takes me a little trial and error with words I'm weak on...)
You just click the link again to get back to the regular rich text editor.