Task Coach - Task Coach is a simple open source todo manager to keep track of personal tasks and todo lists.
Google Calendar - Spend less time managing your day & more time enjoying it
Todo.txt - Track your tasks and projects in a plain text file, todo.txt. A todo.
Jorte - Schedule books must be practical and has a good design.
Strikethru - Strikethru is a kind of to-do list notebook for managing work lists and staying updated with the important tasks.
Business Calendar - Powerful and easy to use calendar app for Android including weather, widgets and tasks.