For those of you running the web browser firefox there's a little extension that I think you might find of use.
SpellBound, it's a spell checker (with an NZ dictionary :-)) extension that allows you easily check the spelling of your posts and comments for blogger and the various forums you might visit on the web.
It works better than Bogger's built in one and can be used for checking the spelling of comments as well. You just type in your text right click in the box and select "Check spelling".
So get it from here, SpellBound.
Note if your not using Firefox as a web browser on your home computer you should be it's only a 5MB download so it doesn't take long to get and install. It's more secure than IE and will stop all the silly little pop-ups from appearing. It also supports RSS and Atom feeds, which are the cool little things that the more tech aware of us use to read all your blogs quickly and easily.