The fine folks over at RedBallon Labs (I need a cool name like that) have written a series of articles on integrating BlogCFC and GoogleSpell. You can start here and work yourself backwards through the Related Entries list.
This is pretty cool. I use the Google Toolbar myself, but this can come back to bite you when you aren't on your own machine. Luckily my speling is near perfect so I need not worry about it.
RedBalloon's article would also be of interest to anyone wanting to add some spelling tools to their web applications, so check it out.