Event2ToDo for Mac

From Ryan Cuthbertson:

Lets you create To Do items in iCal with start dates as well as due dates. This is useful when you want to enter a task into iCal but you don't yet want it to appear with all the others in your To Do list because you can't start working on the task yet. Simply create an iCal event representing the start date of the task, put any due date in the comment, and attach this AppleScript as an Open File alarm. The event will automatically replace itself with an item on your To Do list when the alarm runs.