If there were any lingering doubts about the Mac’s penetration of the enterprise, they were dispelled on Thursday when Microsoft announced it would ship its Outlook e-mail client in Office 2008 for Mac Business Edition next year. Outlook will replace Microsoft’s free Entourage e-mail client in the Business edition, but not in the Home and Student editions. Outlook for the Mac will be built from the ground up with Apple’s Cocoa framework to provide improved integration with the Mac operating system. It will also give enterprise users rights management capabilities.