Outlook 2002 and 2003 support Autocomplete. When you send a new message or reply to one, the address is remembered by Outlook and the next time you send a message to that person, you can type just a few letters and it completes for you.

Occasionally, you'll have a bad address in the cache or just have addresses in the list you don't want saved and will want to remove them from the cache. To remove just one address use the arrow keys to select the address and press the Delete key. You can clear the entire cache by deleting the *.NK2 file for your profile. In Windows XP or 2000, it's in the hidden folder C:\Documents and Settings\username\Application Data\Microsoft\Outlook. Outlook will create a new NK2 the next time you use it.