There's a cool little script that's being linked to all over the place that I wanted to share with you - an AJAX-based PHP spell checker from Broken-Notebook.com.

On his sample page you can get an idea of how it works. You enter the text, hit "check spelling" and hands off the text to a pspell function (requires that pspell be compiled in). When it comes back, it replaces the words it thinks are incorrect with links that you can click to select a "more correct" word to replace it with.

It's a pretty slick little tool that shows one of the more flexible uses of the XMLHttpRequest (AJAX) technology that I've seen. The source code is availible here.