Microsoft's Mac Business Unit this morning said it plans stop developing its Entourage email client for Apple Macs, replacing it with Outlook for Mac -- adopting the Redmond company's primary email brand. Microsoft's top Mac software executive says the goal is to improve the experience for end users, particularly those using Macs in conjunction with Microsoft's Exchange Server.

Despite speculation in advance of the announcement, the company did not discuss plans to release a version of Office for Apple's iPhone. Responding to a question on a conference call, Eric Wilfrid, general manager of Microsoft's Mac unit, told reporters and analysts that the company wouldn't be making any iPhone-related announcements today.

At the same time, Microsoft announced plans to streamline its Office 2008 for Mac editions from three to two in September -- continuing to sell the Home and Student Edition for $149.95 but also adding a new version, Office 2008 for Mac Business Edition, that will sell for just under $400, the same price as the standard edition, which will no longer be produced.

Microsoft currently offers a "Special Media Edition" of Office 2008 for Mac, which will no longer be produced. It sells for just under $500 and comes with with features for working with music, video and other digital media.

The new Business Edition will include features such as document collaboration and a souped-up version of Entourage 2008, dubbed "Web Services Edition." Microsoft said Entourage 2008 Web Services Edition will be made available for free today to existing Office 2008 for Mac users who have updated their systems, via this download page. 

The company decribes that enhanced version of Entourage as a prelude to Outlook for Mac, providing better synchronization with Exchange Server, among other features. Microsoft says the new Outlook for Mac will be built from the ground up with a new back-end database and features including information rights management, to control how emails can be distributed and forwarded after they're sent.

"Outlook for Mac and Outlook for Windows will be different, for sure, and they will be compatible, for sure," Wilfrid said. "Those are really the two design principles that guide our philosophy in building the whole Office suite."