Come 2003 Microsoft Exchange will be pulled under the company's .Net umbrella - Microsoft's initiative to deliver software as a set of services over the internet.

The most significant change will be a common .Net data store to replace the current Web Storage System in Exchange 2000. Exchange’s core messaging, calendaring and task features will then be incorporated into the .Net infrastructure.

Many firms have not yet moved from Exchange 5.5 to Exchange 2000, released last year, because it also requires them to move to Microsoft's Windows 2000 and Active Directory. So plans to migrate to Exchange 2000 may be shelved and preparations begun for a jump straight to .Net.

The next generation of Exchange will also feature support for web services based on XML (extensible markup language) and wireless client access, said Paul Flessner, Microsoft senior vice president for .Net