A mobile worker may want to access information held on Exchange 2003 using a variety of devices. These devices may be holding offline information that has previously been synchronized; however, increasingly the information will be accessed online and wirelessly, through a mobile phone or PDA. In recognition of this, Microsoft has introduced a number of new technologies, previously found in Mobile Information Server 2002, with Exchange 2003 and anticipated a much wider range of devices to be used in conjunction with Exchanger 2003.

Exchange ActiveSync is a server-side technology that allows Windows Mobile-based devices to synchronize inbox, calendar, and contacts remotely with Exchange rather than using a desktop PC, cradle, and desktop synchronization software. In certain cases, for example with a Windows Mobile-based Smartphone or Pocket PC phone edition device, synchronization may occur directly over the air using a built-in wireless modem.

New to Exchange 2003 is the ability to synchronize Windows Mobile-based devices by sending a notification message to the mobile operator, then to the mobile device causing the device to start the synchronize process. This up-to-date notification allows the mobile user to have their device kept up to date with information, allowing for greater productivity and less time synchronizing data.

Additionally there are improvements for users who want to read their e-mail directly on their browser-based mobile devices, or any mobile phones using a HTML, xHTML, or cHTML browser. Outlook Mobile Access provides an enhanced experience for accessing Exchange PIM information using mobile browsers.