This post is a compiled version of Steve Cavanagh's blog post on How To: Spell Check an InfoPath form displayed via XmlFormView. Many are not able to follow Steve's instructions due to lack of details. See below a downloadable zip of all changes need installed for your InfoPath Spell Checker.

File Contents:

• CustomSpellCheckEntirePage.js - This is a customized SpellCheckEntirePage.js which includes changes outlined in Steve's post above.
   
• FormServer.aspx - Note that this will replace the exisitng FormServer.aspx - this file acts like a masterpage for all infopath forms. So this change will add the spellchecker to all infopath forms in the sharepoint farm. Only thing i changed here is to add the 'Spell Check' link before and after the form.
   
• ReadMe.rtf - Contains instructions where to copy the files to in your MOSS WFE server.