We’ve previously showed you how toquickly create appointments from Tasks in Outlook 2007and works the same in 2010.
Then create a Subject, Location, Time, Description, and categorize it if you want.
When you’re finished choose Send or Save if you didn’t invite attendees.
The appointment will appear in your Calendar.
The recipient gets the appointment information and can select to attend or change their response before sending.
Then verify you want to send the cancellation to the other Attendees.
Then the Attendee will also receive an email advising them of the cancellation.
And Gmail as well!