ieSpell is a free Internet Explorer browser extension that spell checks text input boxes on a webpage. It should come in particularly handy for users who do a lot of web-based text entry (e.g. web mails, forums, blogs, diaries). Even if your web application already includes spell checking functionality, you might still want to install this utility because it is definitely much faster than a server-side solution. The program installs as a new button in the IE toolbar.
Its very small program and works great.
http://www.iespell.com/download.php