I just recently started using Google's new browser, Chrome,
and noticed that it has a little feature that puts a red underline under any misspelled words. When you click on the post preview, the corrections are made automatically.
It does have some quirks, like putting the emoticons at the end of the post, instead of where the cursor is. So if you have a spelling deficiency like I do, check it out.

Unfortunitly for NJSTEVE, it does not have a grammer correction feature.