Apple has finally added one of the features I really like in Outlook to Mail and iCal. Now you can drag an e-mail onto the calendar to create a new event. A link to the e-mail message is created in the URL field of the event. Even if the e-mail is moved to a different folder, the link in the event will still open the e-mail. A side note about iCal Version 3 (installed as part of Leopard): the details of events are no longer shown in a drawer. Instead you double click and a metal surface window with the details pops up with a little triangle pointing to the appointment.
It’s an e-mail…it’s an iCal event!