On of the Greatest Misconceptions of Exchange Licensing in regards to Outlook.
I talk to a lot of people at times during Exchange migrations, previous versions to more current versions. And one of the greatest misconceptions there has been, people thinking that the Outlook Client is dependant on their Office CAL’s.
Well, it does not.
So, here I am to set things straight once and for all (Or until licensing changes)
The Exchange Server 2003 user CAL is required for each user gaining access to the server and entitles access rights to both editions of Exchange Server. Each Exchange Server 2003 CAL also includes Microsoft Office Outlook 2003 or Microsoft Entourage 2004 for Mac and permits access from Microsoft Office Outlook Web Access, Outlook Mobile Access, Exchange ActiveSync, or any standard Internet-messaging client.
Pricing and Licensing for Enterprise Organizations (For Exchange)
http://www.microsoft.com/exchange/howtobuy/enterprise.mspx
~ Christopher Kusek