If you frequently use acronyms, type unique names, or have industry specific terms that are not recognized in Spell Check, you may want to add these words to your custom dictionary.  This will save time in your day, especially when sending e-mails.  Outlook should be set to Spell Check all e-mails before sending.  Adding words to the dictionary will speed up the sending process.  This will work in all Office 2010, Office 2007, and Office 2003.  This includes Outlook 2010, Outloook 2007, and Outlook 2003.