GoogleCalendarKit is a project mainly written in ..., it's free.
iCal like Calendar with Google Calendar Sync.
GoogleCalendarKit
iCal like calendar view and Google Calendar Sync API Kit.
Author KISHIKAWA Katsumi http://d.hatena.ne.jp/KishikawaKatsumi/ (in Japanese)
License The new BSD license
Author: Keith Lazuka URL: http://github.com/klazuka/Kal
URL: http://code.google.com/p/gdata-objectivec-client/ License: Apache License, Version 2.0