But that will also change in June, 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.)

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 June, Apple's software update will add an Exchange client, giving you the same access to e-mail, calendars, contacts, and notes as you get in Outlook or Entourage on the desktop. Until then, 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.

[ See InfoWorld's in-depth reviews of the iPhone and iPod Touch ]

For Windows (XP or Vista) shops tapping Outlook 2003 or 2007, syncing 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.

On the Mac, use the built-in iCal and Address Book software as the way station, and then configure Entourage to sync with them (use the Sync Services pane of the Preferences dialog box). In iCal, you must create and use a calendar called Entourage for any entries you want synced to Exchange. (And Exchange calendar items will be placed in iCal in the Entourage calendar as well.) Then, with your iPhone physically connected and selected in iTunes' Devices list, open the Info pane to choose the calendars and contact sources to be synced. All three programs -- Entourage, iCal, and iTunes -- must be set up properly for this ménage à trois to work.

A tip: In Entourage's preferences, choose whether to sync your server's calendar or your local calendar. If you change this setting, it's very likely that your calendar will stop syncing. It turns out the issue is in iCal: You'll see multiple Entourage calendars listed (one for each time you changed the setting in Entourage). Delete all but the "real" Entourage calendar (you can right-click on a calendar and choose Delete from the contextual menu).