Office 365 Small Business Premium is compatible with mail and calendar applications of mobile devices running Android, BlackBerry, iOS, Symbian (see requirements) and, of course, Windows Phone. And thanks to Microsoft's Lync 2010 client, Office 365 users can perform instant messaging, audio calling and audio conferencing with other Office 365 users and can get presence information too. The catch is that it requires a Lync Server or Office365/Lync Online account, and administrators might have to do some manual account juggling if crossing organizations.
The Office 365 portal also provides detailed, step-by-step instructions for setting up the mail client on each supported platform. What's more, there's context-sensitive help that IT admins will appreciate perhaps here as much as anywhere. Our hats are off to Microsoft for the progress it has made with its online help documents.