I just accidentally added a misspelled word to the Google Toolbar Spell Check dictionary.  There is no option to edit the dictionary. But, someone named Jeff also ran into the same problem before, and has shown how to edit the dictionary, so that he can remember how the next time that it happens.  I am posting it here for the same reason.

Basically, you just need to navigate to (replace USERNAME with your own username):
C:\Documents and Settings\USERNAME\Application Data\Google

There's a User Dictionary.txt file in there:

Location of Google Toolbar user dictionary.

Just edit it by double clicking it.  This will launch Notepad, and you will see it is merely a listing of words that you have added to the dictionary.  Go find the misspelled word you just added at the very bottom, and delete that line.

Please note that Application Data is a hidden folder.  If you do not see it, from Windows Explorer, you need to go into Tools --> Folder Options... -->View tab --> Advanced Settings --> Files and Folders --> Hidden files and folders, and select "Show hidden files and folders":

Windows Explorer --> Tools --> Folder Options... --> View tab

Note that making hidden files visible is not a good idea if you are not computer savvy.  Alternatively, you can just type or paste in the path you need to traverse to, and Windows Explorer will let you view the files within the hidden folder.

About the Author:  I am Jason Doucette of Xona Games, an award-winning team-of-two indie game development studio working on Xbox 360 and PC games.  We have released Decimation X, a 1-4 player shmup, which is Japan's #1 best selling #1 top rated Xbox LIVE Indie Game.  We are currently working on Duality ZF, a groundbreaking 1-4 player shmup.  It features dual play, the ability to control two fighters at once, a beautiful electronic Imphenzia soundtrack, and a massively upgradable 32-stage spread/laser weapon system.  4 player dual play allows up to eight fighters at once.  Many of these features are never before seen shoot'em up firsts.  Check out our Duality ZF trailer and help spread the word with our official dualityzf.com website.  Coming soon to Xbox LIVE Indie Games.

*Also known as a shmup or 2D shooter.