Editing the dictionary in Firefox 2

Any entries you add to the dictionary yourself is added to a file called persdict.dat. You have to open that file in notepad, and it'll have a list of the words you added, and you can delete whatever you need to. You can search your PC for that file, or on windows XP go to: C:\Documents and Settings\<Windows login/user name>\Application Data\Mozilla\Firefox\Profiles\<Profile name>\persdict.dat