This fixed a huge issue I had with Apple mail:
I have been using MobileMe since Apple started the service to keep my contacts and calendar in sync across all of my devices wirelessly. Except for a few hiccups early on, it has been a great solution to keep all of my information with me all of the time — on my iPhone, iPad, Windows 7 PC and a Macbook Pro running Snow Leopard (10.6.8.)
Apple’s MobileMe is a great idea. It has been the only real answer to keeping contacts and calendars synced across multiple Apple devices (iPhone, iPad) and multiple computers using both Windows and OS X. Despite a rocky start (see this article) the service has gradually become better and better. But a problem developed for Outlook users when Apple moved to a new calendar format. The upgraded calendar no longer synchronizes your local Outlook calendar with the MobileMe remote calendar (including your alerts/reminders) — instead you get a second, external CalDAV calendar linked in Outlook and stored “in the cloud,” separate and distinct from your local Outlook calendar.