I added a spelling corrector to an application a while back. I tried a couple of libraries that implement these ideas. Problem is it can be slow for big words.

I stumbled across this algorithm which is much faster if you allow some time to pre-process your dictionary. http://blog.faroo.com/2012/06/07/improved-edit-distance-base...

I implemented it here for fun in common lisp. Excuse the ugly code. https://github.com/RyanRiddle/lispell