The second MobileMe web app to undergo a makeover this year following Mail, the all-new Calendar app features a completely re-designed user interface, which Apple says "works best with Safari 5, Firefox 3.6, and Internet Explorer 8". There's a new list view, which displays upcoming events, while day, week, and month views have also been re-created.
There's also been a considerable effort by Apple to improve calendar sharing abilities - you can now share a calendar between multiple MobileMe members which they can also edit and view, or share a link to a read-only version which anyone can see but not edit (no MobileMe account is required). According to Apple, you'll be able to view the read-only calendar on the iPhone, iPad, iPod touch, Mac, or PC (although Apple notes Outlook support is not yet available).
Also, in a move which is sure to help those organizing events, Apple have automated the RSVP system. You can now send out an invitation email to those you want to attend, and as they respond the event on your calendar now automatically updates with attendee information.
The new beta also supports the CalDAV standard - so all your existing calendars will be automatically upgraded to support it. You'll also need to be running the latest Apple operating systems across the board - iOS 4 on the iPhone or iPod Touch, iOS 3.2 on the iPad and Mac OS X Snow Leopard 10.6.4. For more information, Apple has posted an FAQ providing support and upgrade advice.
Paid subscribers to Apple's MobileMe can now request beta invitations which will be handed out over the coming weeks on the basis of first-in first-served.