Something that always annoys me is the lack of spell checking in the whole browser based app world. I have often wanted to spell check input fields in the browser but couldn't and ended up relying on 3rd party tools to do things like blog posts because they have spell checkers.
No more, I noticed via Geek News Central a link to a nice post by Matthew Bishoff that mentions Spell Bound. It is simple to use, just right click on a input box and choose check spelling and it does the rest. More than 30 language files are available.
The Google Toolbar now provides spell checking, although its only available for IE
http://toolbar.google.com/