If you need to bulk edit Active Directory attributes you may find ADModify useful.
Download here:
http://www.codeplex.com/admodifyUsage instructions here:
http://exchangeis.com/blogs/exchangeis/archive/2005/07/01/using-admodify-a-real-world-example.aspxYou may need to define a custom attribute change (tab Custom, see example) to set mAPIRecipient and InternetEncoding)