I currently use a MAC at home and work, and a pda, with ical and address book and tasks synchronised using Mobile ME. Will the new system supersede this, and be as effective?
Yes, this service will support this sort of working. For example a user can be using Outlook at work, iPhone as a mobile device and a Mac at home running Entourage or the native Mac Calendar and Mail clients, each can be configured to synchronise with the Microsoft service. Other users may wish to use Outlook at work and then use the Outlook Web Access to access email and calendar items when out of the office.