What is the point of such an app
iCal is the date handling application for Mac OS X (10.2). Synching it with the Newton would let you keep your calendars in order and take advantage of the capabilities of iCal (e.g. keeping your Newton synched with your pilot or phone, or publishing calendars over the net).
How to do it
Write a plugin for iSync, similar to those for other PDAs, and write the necessary packages for the Newton (preferably using the best techniques of the various similar Newton synching packages)
iSynch with a Newton plugin (mockup)
This project is under development
see the NewtSync site