The truth is that I think that the spell check needs a service by its own.
My thought was to make it a global online service.
it should support all languages by selection.
and correct all spelling mistakes
have to be a smart system that will check all words of the textbox and check if they are on her dictionery.
if they are then 'its good, dont do a thing
else check for other close words and make a suggestion to add the unknown word for the "Web Wiz" dictionery :D
end if
I think that you understand the main idea.
If it's not already exists by ASP...
I can help developing if you'll need help.
It could be a great feature for all web masters... RTE non relited.
Hope that anyone will pay attention for my littel suggestion

.
I want to be involved and updated if someone will got serious, thanks.