Here's one way:
Click view \ current view \ by category. This will show all the items on
your calendar in a table format.
Now right click any of the column names (such as subject) and select "Field
Chooser."
Drag the "Created" field out of the chooser and drop it next to Subject -
now the created time and date will be displayed.
Then click View | Current View | Day/Week/Month to change back.