Exchange ActiveSync – Known Issues http://windowslivehelp.com/solution.aspx?solutionid=e123b840-e6ee-41e7-a302-049da52bf0d5
iOS 4.0: Exchange Mail, Contacts, or Calendars may not sync after update http://support.apple.com/kb/TS3398
How To Setup Hotmail Using Exchange ActiveSync On Your iPhone, iPad And iPod Touch For Push Email, Calendar & Contacts– iPhone Hacks http://www.iphonehacks.com/2010/08/how-to-setup-hotmail-using-exchange-activesync-on-your-iphone-ipad-and-ipod-touch-for-push-email-calendar-contacts.html