Recently, I was asked how to spell check pages at PBwiki, my webhost and employer. I answer all kinds of questions there as email tech support. I don't think I answered that one very well because I told them that PBwiki doesn't offer spell check when you are editing pages. What I should have told them about is the free spell-checker called tinySpell.
I'm sure many of you might remind me that Firefox already supports spell checking in text windows and forms. Sure it does, but it doesn't always work in AJAX driven windows such as WYSIWYG editors. The spell check in Firefox doesn't help the crowds of people who still use IE6 and IE7. For those of you who wish to add spell checking in Internet Explorer, you may want to try ieSpell.
I found that tinySpell worked very nicely in the PBwiki WYSIWYG editor once I'd gotten used to stopping whenever it beeped at me to indicate a misspelled word. When I selected a larger area of text, it also beeped to indicate any misspellings and helped me find where they were located.
I would prefer to get a visible indication when I misspelled words, but I can't complain. After all, it's a free application and it works exactly as it was designed. If I wanted more features, I could pay for a license of the tinySpell+ version.
Quote from the website
Occasionally you need to check the spelling of words in an application that does not include a spelling checker and you don't want to launch your word processor just for that. This is when tinySpell becomes handy. It is a small utility that allows you to easily and quickly check the spelling of words in any Windows application.
tinySpell can watch your typing on the fly and alert you whenever it detects a misspelled word. It can also check the spelling of text that you copy to the clipboard.
tinySpell installs itself in the system tray for easy access. It comes with an American-English dictionary containing more than 110,000 words.