From support.apple.com – ”Symptoms - Immediately after updating to iOS 4, some users may notice that Exchange ActiveSync Mail, Contacts, or Calendars do not sync, or sync very slowly. In addition, some Exchange Server administrators may notice their servers running slowly.

Products Affected
iPod touch, iPhone 3G, iPhone 4, iPhone 3GS
Resolution
To work around this issue, users should install [...]

From the Microsoft Exchange Team Blog:  ”While we appreciate all the positive feedback we’ve received on Exchange Server 2010, we know you all are eager to find out what’s been going on in Redmond since November. Today, we are happy to give you a first look at what’s coming later this year in Exchange Server 2010 [...]

From ARS Technica:  ”Google is continuing its quiet war on Microsoft Office by making it easier for users to switch from Exchange to Google Apps for e-mail. The company has launched a new server-side tool called Google Apps Migration for Microsoft® Exchange, which not only migrates your company e-mail, but also moves your calendar and [...]