What is the difference between Microsoft Outlook Client 2003, XP and Microsoft Outlook Web Access?
  Microsoft Office Outlook Client 2003:
Opens as a program from your computer
Will allow you to create personal folders		   Microsoft Office Outlook 2007:
Opens as a program from your computer
Will allow you to create personal folders 		  Outlook Web Access:
Opens through the Internet
Will not allow you to create or view personal folders
  Transitioning from Outlook 2003 to Outlook 2007: Command Reference Guide