Push email is one of the more interesting features to come to the Windows Mobile world in recent times. It does require both the Messagging and Security Feature Pack add-on (for Windows Mobile 5.0) and the necessary set up on your Exchange server. A free solution from Emblaze Ltd may address that though with an alternative. emoze Personal Edition will push email and PIM data such as contacts and calendar to your Pocket PC or Symbian device.
Right now, emoze supports Microsoft Outlook XP and 2003 but support for Outlook Express, Lotus Notes, Mozilla Thunderbird, Yahoo Mail and Gmail are all coming. It works with Microsoft Mobile 2002, 2003 as well as 5.0 and the Symbian Series 60 operating systems with more to come. On the desktop side, Windows 2000 and XP
are currently supported and Mac OS support is coming soon.
You can also get emoze Corporate Edition (not free) which comes with the emoze Enterprise Server to allow full remote administration and control functions.