The ieSpell tool has been around since I can remember as an available tool either included as standard on the RTE, or available to add on. It currently appears to be standard in the FCK Editor. It's been a while since I used the IESpell tool and it now has some new features that increase it's usefulness and your ability to customize it.
The IESpell tool enables you to create your own unique dictionary of acceptable words. This can be done either by simply adding new words to a dictionary in an adhoc way whenever you are checking spelling, or by creating a text document containing all the words that are ok by you. You have the ability to add and delete words from your custom dictionary at any time which is awesome. I personally can't get the spell checker on my local Word program to update it's dictionary from one document to the next however IESpell remembers all my words every time!
IESpell let's you chose from U.S., U.K. or Canadian English - although I imagine this list can probably be extended. It also has a Look Up Word option which you can set to look up the meaning of the word from one of a range of online dictionaries or similar resources such as Wikipedia, or you can add your own URL to the list.
Another handy feature is the ability to customize the checking options to leave out UPPERCASE words, numbers, etc which can really speed up the tool depending on how you are using the Editor.
