What you can't do today with the iPhone -- out of the box, anyhow -- is get the BlackBerry's push-based approach to e-mail, in which the mail server sends messages to the device rather than requiring the device to query the server to gain access to new messages. This push-based approach makes it harder for someone to spoof the e-mail server. To push e-mail to an iPhone (or most other mobile devices) today, you need a mobile server, such as those from Visto and Synchonica; these integrate with your Exchange or Domino server.
But that will also change in July, when the iPhone 2.0 software includes Microsoft's Exchange ActiveSync technology. ActiveSync lets the iPhone use Microsoft's Direct-Push e-mail feature. (Windows Mobile and Palm OS devices use ActiveSync as well to gain this capability; Research in Motion has built in its own push e-mail technology into its BlackBerry Enterprise Server product.) With Direct-Push, the connection between the OWA (Outlook Web Access) server's mail port and the mobile device remains open so that new messages are instantly visible. (The iPhone does use OWA as its connection to Exchange, just as Microsoft's Entourage e-mail client does for the Mac OS.)
Until the new software ships, you'll have to live with the iPhone's periodic mail checks (15 minutes is the shortest period, though you can easily find SSH hacks on the Web to reduce that window.)
[ Get the whole scoop on the iPhone SDK, how to make the iPhone fit in the enterprise, and the latest security issues that the popular smartphone raises in InfoWorld's special report. ]
Accessing calendars and other shared data
The biggest issue Exchange and Notes shops face today in business-enabling the iPhone is providing access to calendars, address books, and other PIM data beyond e-mail.
Come July, Apple's software update will add an Exchange client, giving you the same access to and update capabilities for e-mail, calendars, contacts (including the Global Address List), and notes as you get in Outlook or Entourage on the desktop. So, you'll be able to accept invitations to meetings, which you cannot do today.
Until the 2.0 software is released, calendars and contacts can be synchronized between Exchange and the iPhone, but this must be done through iTunes, meaning you will need a PC or Mac to act as an intermediary.
For Windows (XP or Vista) shops tapping Outlook 2003 or 2007, syncing today is straightforward through iTunes. Connect the iPhone to your intermediary PC and select it in iTunes' Devices list. Open the iTunes device Info pane and choose the calendars and contact sources you want to sync. If you have problems, consult Apple's common fixes.