As someone who works a great deal with web forms (daddyo.com is edited with a web based interface), one of my favorite utilities is called Hot Lingo – The Web-form Spell Checker. A plug in to IE browsers, Hot Lingo Hot Lingo features a 75,000 word English dictionary as well as customizable user dictionary that can hold 32,000 user defined words.
When you’ve finished typing text into the web form, just right click (as I’m going to do as soon as I finish this sentence) and choose “Spell Check” from the menu. AND, it’s shareware. How cool is that?