- Start > Run > dsa.msc (this opens Active Directory Users and Computers)
- Select the user. On the General Tab, change the email address to an email address that your domain isn't managing (i.e. @yahoo.com, @gmail.com, etc, etc). Click OK
- Open SharePoint Central Admin console. Click the SSP link off of the Home page of Central Admin
- Login (duh).
- Under User Profiles and My Sites > Click User Profiles and Properties
- Click Start Full Import
- After the import is completed, you should view the target user's profile and remove any Proxy addresses.
Next, if the user has already been granted access to your MOSS Web Application, you will need to remove the user and then re-add the user back into their original permissions. Then, when you go to view the user's profile details, they will show up with the user's new email address.