Google Calendar - Spend less time managing your day & more time enjoying it
24me - Next Generation Personal Assistant
Business Calendar - Powerful and easy to use calendar app for Android including weather, widgets and tasks.
Awesome Cal - Awesome Cal is a Calendar application for your iPhone that you can take anywhere and keep close by to monitor all the upcoming birthdays, festivities, meetings, and more from a single place.
Jorte - Schedule books must be practical and has a good design.
Calvetica - The fast calendar for iPhone. Add an event in just two quick taps.