SpellCheck app

I am trying to write a small spellcheck app. I want it to be such that it can be used without using the word.dll which presumes that the user has Microsoft word installed on his machine. Can someone tell me how to write such an app. I am using C#.Net as my programming language.

i haven't much idea other than you will need a dictionary file that lists all valid words. Then you will search for each one, if not found use something similair to regular expressions to show the words it might be.

scroots