To spell check your Facebook posts with Internet Explorer we need to download and install the Google Toolbar for Internet Explorer.
After installing the Google Toolbar you may need to restart Internet explorer to get the Toolbar to work. while in Facebook start typing something on the page and after your done typing click on the Spell Check button located on the Google Tool bar and spell check will highlight words that are misspelled in red. You can then click the misspelled word and it will give you a list of possible words that you may select in a drop down menu. This tool will correct spelling errors but not grammar errors.