The NetSpell project is a free spell checking engine written entirely in managed C# .net code. Package includes a medium sized English dictionaries. Suggestions for misspelled words are generated using phonetic (sounds like) matching and ranked by a typographical score (looks like). Also supports "ignore all" and "replace all" misspelled-word handling. For detail information, please check LoreSoft.com Site.
Please note that: You need to have the .NET framework installed on your web server to use this feature.