If you use firefox as your browser it will automatically check spelling as you are typing in blogger and many other sites. Spell check is built-in and apart of the firefox. Firefox has other add-ons that I like such as ad-blocker (stops ads from showing up). No script, which keeps unknown java scripts from loading.In addition if you are using IE (Internet explorer) then you can download google toolbar. The toolbar has a spell checker that you can use to checker your spelling as well. (Google Toolbar works in IE and firefox). If you decided to use the google toolbar you would click on the spell checker icon in the toolbar to check your spelling then you would left click in an empty area in the text box to turn it off before posting.
Thanks I may try that.